Hex head vs regular 6 side bolts?

[tdoublenastywitit]

What's the reasoning behind all the hex head bolts used on one these cars? (and other cars)

They seem a lot harder to get a bite on, fill up with dirt and grime and since it's a female connection, a lot harder to clean that grime out before inserting your allen bit.

As of now I'm specifically referring to bolts that are used to hold on the engine oil pan and other bits and bobs around the engine/transmission (trans hardline clips, vac modulator, dip stick, etc etc)

All of them are filled with grime and half of them strip out when I try to remove them. I have been replacing the stripped ones with new hex head bolts. If I remember off the top of my head correctly they are m6 x 10 thread.

After thinking about it I would like to change them to regular 6 sided m6x10 bolts (I don't know the proper term, just always have refered to them as bolts) so they are not so hard to clean off and remove in the future.

Just wondering what the reasoning is behind using the hex heads? and if replacing with standard would be an issue?

I also see hex heads used in higher torque higher strength applications (like flex disc and etc) what's the reasoning?