Select has nothing whatever to do with where you sell paperbacks.
And when it comes to ebooks, there are more sales on the other online bookstores than there are full reads on Kindle Select. And if you price at $2.99 and above, you'll always earn more money from a sale than from a full read.
All of my sales are $2.99 and above. When I was in all the other places I sold almost nothing. So yes, I definitely earn far more on k you 2 alone than i did in all others plat forms sales combined.