I'm surprised no one mentions wear and tear. I do rides where people spend a lot of time in the 10t cog, but spending time in that gear and putting power down in that gear is going to cause greatly accelerated wear on the chain and the cog. Personally, I like to be 14t or above when riding hard.
(the weight thing is a fallacy. My bike is lighter with 2x. Lord knows the front derailleur isn't a heavy component, especially compared to a large range 1x cassette (that is going to have to be replaced more often than on a 2x bike.)
But ultimately, the only thing that really matters is riding. 1x is fine for solo rides, 2x is going to be a big help for fast group rides.