^^^it is the best foot ever because you can pretty much forget the pressing and that is good enough.
^^ the rolled hem foot is different because it only does 1/16" and 1/8" hems, and it is indeed for fine fabrics. I actually bough a 1/8" generic foot from a fabric store and it was super cheap, the same foot from brother wouldve cost me at least 10 times more, can you say bargain? haha . the 1/16" is only for industrial machines i believe, i have both.
The bias tape foot is wider, you can feed it up to 1 1/2" tape so you can end up with a 1/2" trim. And as EIR says, you can match it to your own fabric or create your own combo.
I never did buttonholes by hand. At school we have a device that does buttonholes automatically but completely ruins your fabric unless its denim or similar. It has a dented bottom so it can hold to your fabric but its awful. My home machine can do them in 2-4 steps but its not as easy as it sounds, i had to practice a lot before i could do the perfect buttonhole..actually i still am.
^be careful, looking for different mfeet is seriously addictive. haha