Yes, the weapon of warning; immunity to surprise, advantage on initiative (worth more in most fights than +1 to hit/damage), and also penetrates "resist nonmagical BPS".Hat of disguise & weapon of warning along with many other things are also on that same table.
Hat of Disguise, which (barring a high magic world where there is constant truesight/detect magic spam) impersonate almost anyone, carry weapons almost anywhere, etc. You can step into a corner and come out someone else, all day long.
Pretty major magical power. Even half decent for combat; if you are roughly the same size as your foes, you can mimic any one of them and pull off a pretty good ambush.
I can see how the +1 greatsword is way less impactful. It is mostly just a slightly sharper sword. I mean, it does swing damage and accuracy a bit, and in the hands of a GWM -5/+10 that bonus accuracy can be big.
Honestly, to me, the main advantage of +1 weapons is that they don't require an attunement slot. At low levels this doesn't matter; eventually, running out of attunement slots isn't all that rare in most games.