My main concern with this card is that to make use of the agenda searching option, you need to have 2 available, as trashing to search puts the agenda on the bottom, then you need another copy of her out to draw from the bottom of the deck. Unless of course you have a way to bring her back from the archives to re-install. Aside from cards which give benefits when things are installed (Turtlebacks/NEH etc) I feel that fast track is better.

Or am I missing something with this that I haven't realized?

Unless the runner is running Showing Off, sitting on the very bottom of R&D is pretty much the safest place an agenda can be in - unless you're looking to shuffle in the future. So, there might be some value as a niche way to hide one agenda. —
Just hide this Goverment Takeover on the bottom and be done with it. —
She can also help you dig for stuff through an R&D-lock. Let's say you need options, but your opponent has R&D under lock and key. You're in a situation where you need to draw, but if you do, you let the runner access more cards. Here, Shannon can get you options while keeping R&D stagnant. —
If you were looking for agenda tutoring you'd just use Fast Track anyway. —