True... you could indeed.
TBH, depends what you want to do with the number afterwards. If you are continuing to do math with it, then round is a better function. If you want to output it for display, then number_format is probably the better function, since it will insert thousand seperators (,) etc, which you can of course customise and looks nice for the user.
I assumed he would be dumping the contents to a user, hence the number_format suggestion.