Since most non-developer users don't use or know Markdown syntax, it would be great to have a rich text editor, or even something simple like this comment box on issues here in Github. If you want to add an inline image, or a link, you can't technically do that from this formatting list, but if you know Markdown you can. Users don't know markdown though.
Having the ability to add inline links, images, etc. would really be a game changer for CRM-style applications, and would save Glide Developers of taking an extra step on or off Glide to re-format Markdown into HTML for emails.