For most stuff, 64-bit makes surprisingly little difference. And it adds the complexity of needing to release two versions or an installer with both in it, which increases your bandwidth. VLC only uses about 5% CPU on my i7 to play a 1080p AC3 video. For most end user stuff, the difference of 64-bit is unnoticeable, a 1-2 % difference maybe. For certain things, it matters. Things like encoding or compression. Compressing files in 7-Zip can see a 5 to 10% increase in speed, for instance. If you routinely compress a lot of files that take minutes to package, it can be noticeable and add up.