This is hands down one of the best cards that can be gained from dead companions. I have tried it in a Leo Anderson deck (yes, I know all allies look better with Leo) and it perfectly complements his weak points. Most importantly, Anyu can always do something useful for you.

First, it can be an improved version of Pathfinder, letting you move in any window. You will use this most often.

Secondly, it can be the equivalent of a Well Prepared + Mitch Brown combo, giving you +2 to whatever test you need some help passing. It's worth to mention its own combination with Well Prepared, which will help you with the following point and in general is an outstanding upgrade in Edge of the Earth.

Finally, it can be a free evade action with a +3 (for Leo, a +1 at least for most investigators).

To top it off, Anyu can combine the 3 of them in a clutch situation to evade with 6 and then move; move, evade and investigate with +2 or any other busted burst you need.

Obviously, not all is perfect and it occupies the contested ally slot, but the free actions it provides can very well make it a better fit than most other allies in certain contexts. It's actually so good that it merits the investment in Charisma a in a deck with 2 other allies.