STEP math exams relavent in the US?

Basically the title. Are the Cambridge math STEP exams considered of any value to US colleges? Maybe as a substitute for AMC/AIME if I’m applying as a math major.

I haven’t heard of them being used. But that being said, if you receive an S or 1 on STEP 2/3 I have to believe that top universities here understand the difficulty of the papers and level of achievement needed to achieve those sorts of scores.

But if you can achieve those scores, why not go to Cambridge in the first place? I couldn’t imagine that any undergrad program here would be better (maybe Harvard and Princeton would be equal).