The basic Switchblade is, I'm afraid, the lamest weapon in the core set. It's got a couple of nice features; being fast saves an action, and it's low cost makes it feasible to play in a hurry. Sadly, though, it doesn't offer much. A strength bonus is a big part of the reason for playing a weapon - and this offers none. The damage bonus is nice - but how are you going to manage consistent successes by +2? Weak enemies with high-health are pretty rare. Honestly, you're not going to make that +2 often; and so it is a bit of a waste, unless you can find some strange combination in the future. It doesn't even offer decent skill icons.

However, it's major redeeming feature is it's upgraded version - the Switchblade - which is worth a look.

As others have noted, weapons that don't give you a strength boost, allow you to use another stat for the Fight action, or some other jankery are pretty weak. This cards low cost and Fast play action are of limited saving grace.

Unless, you have an Investigator that doesn't need the strength boost. Enter Tony Morgan. With a base 5 combat, starting Tony Morgan is well-equipped to smash things with Switchblade. Add in Opportunist and you have a cheap way to mash up some enemies.

Still not amazing, but Tony provides at least a solid place for Switchblade to be useful in a starting deck, especially if you're looking to fill out his asset slots with 1-2 additional weapons.