M68K also had single-bit instructions. Way back when I wrote M68K assembly, I used them a lot.

I'd think there are quite a few data structures and algorithms where there can be benefits of using powers of two, or to count bits in a word.

RISC-V without the B(itmanip) extension is otherwise quite spartan. B also contains many instructions that other ISAs have in their base set, such as address calculation, and/or/xor not, rol/ror, and even some zero/sign-extension ops.