I am wondering if it is worth pointing out that currently there is no way for a user to start typing in bold or italics right away without highlighting the text so for the toolbar to appear.

He can do this via keyboard and works quite well as I see here https://wordpress.github.io/gutenberg/ but there are many people out there who are not familiar with keyboard shortcuts for bold, and rely on the B and I icons.

Perhaps this is too much of a stretch at this point as there are more fundamental challenges to workaround, but it might be worth considering.