> IMHO a 6502 is too limited to be effectively programmed in C; even this part of the article gives all the limitations: https://nesdoug.com/2015/11/15/2-how-cc65-works/

In my not so humble opinion, almost all of those are limitations of a compiler, not of the CPU. Then yes, on a 8-bit CPU, you'd better avoid larger words unless you really have to or it will be slow.