Gunk build up wont be an issue if you run the motor hot enough(good driving cycles), use premium quality oil, and stick to a regular oil change interval. It's basically a waste of money. That's just my 2 cents however. A piece of mind is always a valuable asset and that's what it brings people. You also have a point about the repetitive use. I can't say I've ever heard of issues with seafoam from owners whom use it often and early. Mostly people whom use it first time on an older car. Googling "engine knock after seafoam" should raise some eyebrows however.
Lima... where the men outnumber the women and the women outweigh the men.