It is lazy, but here's a good reason to not use Web Mercator: Unlike regular Mercator, Web Mercator is not conformal. Mercator preserves shape locally, but Web Mercator distorts shapes by +/- 1%-ish depending on latitude. Web Mercator doesn't do the thing that makes Mercator a good projection.
Does that +/- 1%-ish actually matter? Maybe, I dunno. It annoys me though.
It is lazy, but here's a good reason to not use Web Mercator: Unlike regular Mercator, Web Mercator is not conformal. Mercator preserves shape locally, but Web Mercator distorts shapes by +/- 1%-ish depending on latitude. Web Mercator doesn't do the thing that makes Mercator a good projection.
Does that +/- 1%-ish actually matter? Maybe, I dunno. It annoys me though.