I'm a newer player. A friend and I are playing through every campaign in a row. So far we have gotten to Dream Eaters, which needed us to make secondary characters. We both included this card in our decks for those characters (our "interns").
I found this card to be seriously mediocre on first reading, but after thinking about it more there were some situations where taking it makes sense. I will agree with the other review that the "correct" use of this card is to make swapping out to another investigator mid-campaign less painful, but I think that isn't the only use. I would not use it for every character or every campaign, but there are a few situations I think it is worth using even from mission one.
What does this do? In essence, it significantly front-loads your character's power curve. Your character goes into the campaign significantly more powerful than they otherwise would, at the expense of not having as much experience available at the end of the campaign. If you take this and In the Thick of It you can start the game with 13xp, not even counting any other shenanigans involving characters that start the game with xp, or other ways to upgrade cards without paying experience (for example, my character for Dream Eaters uses this and Down the Rabbit Hole to start the game with some unspent experience, then gets more value for it over time).
That seems like a bad deal initially. Campaigns are usually easiest in the beginning and get harder over time. Why would I want to make the already easy part even easier at the expense of making the hard parts even harder? Since this card significantly distorts the difficulty curve of a campaign, let's think about campaigns with weird difficulty curves.
Some campaigns start very difficult, then ease off for most of the rest, so being stronger at the beginning is actually helpful (Forgotten Age springs to mind). Some campaigns are very short, or otherwise don't give much experience, so you aren't really losing that much with this card (the intro campaign, or one half of Dream Eaters). Lastly, some decks just don't need all that much experience. They're fully functional at ~15 experience and don't get significantly better beyond that. In any of those cases this card is mostly upside.
Another hidden upside to this card is the simple fact that you no longer have to care about gaining experience. For us, that has definitely changed how we play the game, and can be surprisingly freeing. Victory locations are meaningless to you so there is no need to try and investigate them unless it contributes to completing the mission. Same with victory enemies. Don't even try to fight them, just evade them or otherwise go around. Heck, Unsolved Case, which taunts me every time I play my main character of Joe Diamond, is a completely dead card in a deck using Ascetic.
I have found this lack of care about experience to actually make the game easier, which is a potentially hidden upside.
Anyway, I hope that made some sense to you and may have encouraged you to take this card in a situation you otherwise wouldn't. I'm sure there are many things I haven't thought about, so please feel free to point them out in the comments. Have a great day and thank you for reading all this!