So for me the obvious comparison for this card is Cryptic Research, as they are both high XP, fast sources of card draw.
Cryptic Research has the advantages of being guaranteed card draw and costs one fewer XP. All In has the advantages of being able to draw you more cards in the best case scenario, not being able to draw weaknesses, and having two wild skill icons. 5XP is a lot to pay for an Unexpected Courage so I imagine this is mostly going to be used on easy skill tests to try to draw a bunch of cards, but there's always the option to commit it to a difficult test that you have to succeed, so I suppose its an upside.
Personally, Cryptic Research has never quite gotten there for me, and I never find myself with enough spare exp to justify running it. In theory, Rogue's should have even less spare exp floating around, so if this is really just the green Cryptic Research then it's terrible, right?
Well, maybe... but probably not! I don't think All In is a card that you can throw into a random late campaign rogue deck and expect to get value out of, I think this card is actually a big pay-off card for the "Succeed by Two" archetype. The ideal combo turn for the succeed by two deck looks something like.... find an easy test like a low shroud location or low fight enemy, attempt it and commit some combination of Watch This, Quick Thinking, Double or Nothing plus whatever cards you need to feel confident in over-succeeding, and then gain a bunch of extra actions and money and maybe a card if you had Pickpocketing or a Lucky Cigarette Case.
Enter All In.
With the +2 this card gives you to the test you can reasonably expect to be drawing 6-8 cards off your big combo test, even on hard or expert. What this does is let you add a huge injection of cards to that combo turn, which can then let you really get maximum use out of all those extra actions, and then end your turn still with a full grip of cards to let you combo off again next turn. This is all of course very risky as drawing the Tentacles on your big test can ruin your entire week, maybe you can convince your friend to play mystic....