It's more flexible than Crisium Grid and protects all servers against a variety of threats. Problem: it's a low-impact card in many matchups, and there are so many 4/2s and 5/3s you could have played instead. Offshore Office -- by no means a top-tier agenda -- is 7 credits upfront. How long will it take your Transport Monopoly to produce 7 credits worth of value?

Popular "if successful" cards:

• It absolutely guts Apocalypse. They have to make 3 runs and then you prevent the third run from being declared successful. Then repeat this the following turn. Most Apocalypse decks do not have enough economy to run that much.
• Diversion of Funds. A Diversion of Funds that goes through is up to a 10-credit swing effect. If Transport Monopoly kills even one Diversion, absolutely worth it.
• Almost every runner (81% as of ban list 21.06) has Dirty Laundry. If you score Transport Monopoly, you could cut $10 from the runner. That's not terrible value for a 4/2. In some matchups, e.g. Shaper, this is probably the best you can hope for.
• It sets back Stargate 2 turns.
• It shuts down Counter Surveillance.
• It's a minor delay to Conduit. They could just run again.
• Hot Pursuit.

For reference, as of ban list 21.06, here are the most commonly used cards in standard which check if a run is successful:

• Dirty Laundry (used in 81% of runner decks)
• Stargate (29%)
• Apocalypse (27%)
• Diversion of Funds (20%)
• Conduit (16%)
• Hot Pursuit (10%)

(Minor examples include Embezzle, Wanton Destruction, Khusyuk, Steve Cambridge, CBI Raid, and Legwork).

I've said this before, but I'm not the best at Netrunner. Now that that's out of the way...

Transport Monopoly honestly feels like a weaker version of Crisium Grid for two major reasons. First, it's an Agenda. Whereas Crisium would set the runner back 5 to dispose of it, the second they see it, they take it out of your hand and place it in their score area (unless they're running Film Critic as their restricted card). Furthermore, you can't spend influence to splash it elsewhere. Second, it has counters attached to it. Sure, Mark Yale lets you reap benefits from it, but unless you're placing it in Titan, it's a blank agenda after its second use.

That isn't to say this is a bad agenda; I just wanted to point out the glaring weaknesses before explaining why this agenda is good. Sure, it's not a hard end the run like Nisei MK II or Border Control. However, it does block some annoying card effects for the Corp. Khusyuk? Guess what, you're looking at the top card only. Dirty Laundry? Nope, you just wasted two credits for a run. The Maker's Eye becomes much weaker with one of these scored, and you can forget about fetching your killer lady with a Retrieval Run. Furthermore, this can be used in conjunction with Crisium Grid. You put a Crisium in the wrong server and the Runner's about to get those needed 9 credits from Hot Pursuit? Nope! Shut down with the Monopoly! And this Monopoly won't end friendships! Probably.

Final thoughts: Although a bit weaker than Crisium Grid, Transport Monopoly can be quite useful in a Weyland deck. It shuts down Runner cards that rely on successful runs, and can be fired on any server. Furthermore, although it's a once-per-turn ability, you can act like a classic thousand-cuts Jinteki and fire three off in a turn provided I'm not misreading that. If you need an extra two or four points in a Titan deck, this should benefit you greatly.

This agenda exists pretty specifically for Earth Station: SEA Headquarters. When running Earth Station, you can force a 6 credit tax on your remote, but the runner can disable it by running HQ. You can do your best to ensure a crucial HQ run will be more than six credits, but runners have a lot of tricks for easy HQ accesses. S-Dobrado can let them skip two ice, while Inside Job (which works on all servers not just centrals) only does one. Backstitching can cut through your ice if HQ is the mark. Sneakdoor Beta can just absolutely devastate your taxing HQ, and while they might not be able to use their events when sneakdooring, they are very capable of flipping your identity. Transport Monopoly gives you the ability to force them to need to hit HQ twice on two different turns to flip your ID, or just eat the six cred cost when normally they wouldn't. Crisium Grid serves a similar purpose, but this being an agenda has drawbacks and benefits. It can be stolen while Crisium has to be trashed at a decent cost, but being an agenda, it can't be trashed at all. Once you score it, it exists, and you don't have to use it on non-crucial turns. Putting down a Crisium might save you once, but if the runner skips that turn to run and trashes it next turn, it's gone. If they don't run with Transport Monopoly up, you just keep the charge.

Outside of Earth Station, its use is more limited. You may be able to prevent game-winning Legwork or stop a Burner from bottom decking all your economy, but you can't guarantee it'll happen every game. Not useless, but far more of a kind of meta call.