Not totally useless, when incorporated with other pedals it can make some interesting sounds. Decent slapback effect and vintage echo on its own. Very cheap quality but it's only ~20$ so what do you expect.
First time I got this, I was so happy to have a sort of delay pedal. Five minutes later, I'm wondering why this thing is stuck on slapback.... Sure, you can make some good sounds, but after a lot of tweaking, the only feasible setting is to set the mix and repeats all the way to make a sort of pseudo spring reverb.