Oh I know. I'm just a luddite, and refuse to run 7.x on anything capable of running 6 or earlier.
I don't think it's stupid, I see where you are coming from...keep the machine true to its vintage default and don't overlog it with bulky later-released OS software that will lag the processor and sacrifice performance, stability, and compatibility. It's kinda like how I hate using OS X on my Pismo PowerBook, and would rather use all my apps in OS 9. Both will run fine, but I think those Macs are really built and equipped for Classic, and the Aluminum-book series and later are built for OS X.
System 6 is fast, speedy, and runs on very little RAM. It's also quite stable. I think the System 7 Finder makes it easier to get around, open, save, move, rename, and such....but you are hogging more RAM and sacrificing a bit of speed when you use an old 68000. But yes, I totally understand why you'd want to run the default and keep it there.