I have been entranced by 2.5s for years and because I use that cut often I usually cut small scraps into strips or squares of that size. Long ago I tried to cut all of my scraps into standardized sizes but found, like others who responded here, that I did not use them or had to re-cut them.
For my two cents, step back and consider the sizes that draw you in and that you find you use often. Cut scraps in those size(s). If you are going to invest your precious time in cutting, make the sizes that YOU use. By the way I do sort my 2.5s and 2.5 strips by color. That is soothing and useful in my sewing room.