As @maruru said it probably depends if you know the specific number of rows and columns. I always use flexbox and try to avoid float, 'cause it requires fixes a lot of times and for me that did not learn using floats, floats behave in a weird way 'cause their parents don't mind the height of the childs which is often a problem specially if you don't know if you're going to need 1 or 50 rows so that's it, at least for me.