If you say what's the point ripping amiga sprites, then why not take that view with most of the screenshots in HOL? Why not use arcade screenshots for MERCS instead of the amiga ones?
The answer is because it's an amiga database, and the whole EAB thing is about amigas. The sprites are for preservation purposes as much as anything so preserving as much of the games as possible is what is being done. For the AMIGA
