Or for people with bad connections. If you expect high latency it can be worth it to embed js code to avoid the additoinal roundtrip. 10kb makes a big difference for that.
Inflating the document size does impact paint time, but it scarcely matters here.
Until that I believe this argument is equivalent to “what about Mars”. By supporting dead slow connections on Earth you simply support them to remain so.
Literally none...this is just the argument of contrarians or people who've only ever worked on personal projects who take offense to real applications used by actual audiences.
You don't embed same piece of code on every page request but instead you make the code cached on first download.