On a daily basis, i paste into programs that aren't wysiwyg (terminal, reddit, browser omnibar, etc) much more often than stuff that is (google docs, powerpoint). for the former programs it doesn't matter if i paste with or without formatting.

for the latter programs having the default be paste with formatting seems fine. yes, i'll paste stuff from the web without formatting. But copying/cutting/pasting within the same document is also a pretty common interaction and if i'm cutting something non-trivial (eg. google docs table/nested lists), i don't want to paste it back into google docs as a bunch of regular, separate lines.