This card is much more potent and insidious than it first appears.
The effect of adding 3 [curse] and 3 [bless] to the chaos bag is not why I would consider running Tempt Fate. All that does is to increase the volatility of the chaos bag, unless you have a way to leverage blesses and curses (which I'm sure will be coming out in this cycle - I'm writing this review as of Innsmouth Conspiracy).
The secret effect of this card is that its a 0 resource, fast card (that can be played in any window), that says draw a card. Discounting the bless and curse mechanic for a minute, this is a completely free "cantrip" (or card that replaces itself). So it costs no actions nor resources to play and the only real opportunity cost to use it is to include it in your deck over something else. So lets think about that cost as a benefit.
There is speculation in many card games that such a cost-free cantrip would see play at the highest levels because it makes your deck more consistent. Effectively it can be considered to be "water" because it will always be played straight away and replace itself straight away; it might as well be considered not in your deck for most purposes. This means that you are effectively breaking deck construction rules by packing 2 less cards than your deck size, therefore making it more consistent.
Fortunately Arkham Horror is different to most other card games: card draw for us is not necessarily king, owing to every deck having at least one weakness that it mostly doesn't want to draw into. However, digging deeper that's not really true - most weaknesses can be handled, but you just don't want to draw them at the wrong time. So given that you can control when to play the cantrip, the main reason against making your deck smaller can be ignored with smart play.
Do you run Prepared for the Worst / Tetsuo Mori to get away with running fewer weapons in guardian? Tempt Fate too.
Do you use Mr. "Rook" to help find specific cards or to set up a combo? Tempt Fate too.
Do you ever spend experience on cards and want a higher chance of finding your powerful cards each turn? Tempt Fate.
I fully expect this to get hit by the taboo list; such consistency feels like the sort of thing that gets put onto XP cards. I only hope it doesn't set a precedent.