As others have pointed out, while it's easy at a quintessential level, it's not easy if you're dealing with actually complex (and clever) structures.

I don't know if you've ever had that experience in your OllyDbg-using days, but did you ever try to analyse software that was using some form of hashing function, or cryptography (ECDSA, for instance) with OllyDbg, without knowing what it was? The idea is kind of like that. While it's easy to get a concrete idea of what that block of code is doing (feed it an ASCII string and some memory structures, it spits gobledygook out), it's not so easy to look at it and conclude "Ha! This implements AES-CBC!" without some strong intuition or experience.