Just to build off what -DH has already said. ProRes was designed to be a high quality, low bandwidth (relatively speaking) alternative to editing uncompressed HD (which can require large, fast, expensive storage). When Pro Res first came out the tag line was something like "HD quality at SD size." ProRes does 8-bit color and ProRes HQ does 10-bit color.
basically prores is for display editing only. It's not designed as output format. We use it with 4x1080p resolution usually. This is a common use. Most of these formats are too large to use h.264 when editing even on the fastest computers but with prores it can be done.