Yeah, that was a different product with the same name. The ATM I worked on was a low level font rendering utility. It became obsolete in a few years as Windows evolved to include a formal font driver interface, so Adobe repurposed the name for a font management tool.

I'm a little fuzzy on those details, but I seem to recall that there was a problem with having too many fonts available at the same time. (Memory limitations?) So this new Adobe Type Manager let you select a subset of your fonts to be available at any given time.

Up to Windows XP, having many additional fonts registered notably increased system boot time. It silently did full font enumeration on start, like fontconfig without cache does. That's at least one problem.