I don't find browsing the archives much different than online forums,
except that all the posts are listed at once.
As for why not a Yahoo group, the list predates Yahoo Groups by almost
three years. The oldest message in the archive is from June of 1998,
but it had been running for some time before that. I keep a lot of
email. but can't find the original posts to the list, or any announcing
it, so it may stretch back further than that. I've always run it on
my own server, so when it breaks, it's on me to fix it, and I know that
it'll never be pulled out from under me.