bold, italics, etc. are used to indicate context

How can you guarantee they are? There are no technical restrictions or instructions on how much or where you can use emphasis and strong emphasis in your message. Until that’s not the case, “italic” and “bold” should be treated as purely presentational markup.

used for accessibility purposes

Screen readers do not and should not care about presentation; abusing semantic markup to indicate through emphasis that something is italic or bold is anti-accessibility.