I use folders to sort my music. I have an album where I had 3 of the songs from a Greatest Hits compilation and then later bought the rest of the songs on the album by themselves.
The filenames are 01-Song 1, 02-Song 2, etc. so in a music folder they are in the correct order.
Poweramp is sorting them by the album though (02-Greatest Hits, 05-Greatest Hits, 07 Greatest Hits, 01-Album , 03-Album , etc.) and I can't find an option to sort by filename.
(another example is an album where the play order is different than released - the filenames are numbered in the custom order but P