VisualEditor doesn't provide a way to immediately see the current formatting applied to a text, and to the text you're about to enter.
In most cases, this isn't an issue because the text itself shows the formatting (e.g. bold, italics etc.) but in other cases it's not that obvious. For example, punctuation marks like colons, commas, quotes etc. are small enough it's difficult to see that they're in bold / italics etc.
This results in formatting being applied by mistake by some users, and other users being unhappy with VE because it facilitated that user error. For example, adding a comma after italicized text will also italicize the comma. This is normal VE behavior, but if the comma shouldn't be italicized, it's currently difficult for the user to see that it needs fixing.
In many text editors, one way to identify basic formatting is to look at the toolbar, where the "Bold" or "Italics" buttons are shown as pressed if the text is in bold or italics; it's not ideal because it's away from the cursor, but it's a clue. VisualEditor shows this with a gray background, but since it's hidden in the formatting dropdown, it's not immediately visible so it fails for the purpose described here.
Another common clue provided by text editors is to format the cursor itself to reflect the current state of formatting. For example, the cursor might be slanted to indicate that the text about to be typed will be in italics, or the cursor might have a heavier font weight to indicate bold. This provides a clue to the user about the current formatting.