I understand what a class is but am confused as to why so many people are
using them for what appear to be very simple PHP applications. I guess I
dont know enough about how they are useful.

for example I've just seen a "who is" application thats just 2 files
and a few dozen lines of very simple code

But the author put the thing into a class. This just seems to complicate
the code without providing any benefits as far as I can see.

Can someone explain what the advantage of this is please? And any advice
on when or when not to use classes would be ful?

cheers

Col.