Please do not forget the other side:
Sometimes it is important to add content that is not wrapped or
otherwise disturbed. Until now I can at least use the email interface
for this.
One example: SHA256 fingerprints with colons are 95 chars long:
24:D1:12:E1:A0:54:09:88:F1:03:E5:53:EF:00:3D:72:F6:82:E8:0F:25:EA:F0:BD:41:81:4C:29:F1:DD:8B:B1
and since I do not want to compare such long hashes myself, I just feed
them to "grep", which does not get easier if I have to reconstruct the
original line.

If you need more wrapping in the web interface, maybe CSS
word-wrap: break-word;
would help, which would add breaks even within what the browser thinks
to be a single word.
But this would survive e.g. copy&paste.