Using instead of

I am fairly familiar with HTML but only looking into epub format tonight.

I started a book in Kindle Create which produced some problematic code and I have switched over to Sigil to clean it up.

I noticed two things right away.

First, every single content block had it's own class and id and every chapter had it's own style sheet. I am not sure if that is just an artifact of Kindle create or is something set by the epub format.

I created a single style sheet with styles used throughout the book and streamlined all those redundant classes. Hope that won't cause any problems... would it?

Second, simple paragraphs seem to use <div class="class-01"> instead of a simple <p> tag. Is there a reason for that, or could I just use <p>?

I tried googling the answer but just got a lot of unhelpful results.

Thank you so much