Wow man, calm down
Firstly, you didn't posted in the good section, so post moved
Then, about your question, here is my answer, but maybe not totally right (But I'm pretty sure it is
BIN files are the official acer roms. They also contains the baseband of the phone, which contain mainly the radio.
Custom rom, in zip format, are full rom. They are based on a certain baseband, that's why each rom recommand its own bin file (mainly, they are all based on the latest one available).
Hope this have answered to your questions.
Samsung Galaxy SIII
Samsung Galaxy Tab 10.1 (P7510)