I was wondering the same here a while back. I now feel the ASO is independent of how much we charge for an app. For example, I changed some of my sticker packs to paid status and didn't see any effect in number of impressions. What did happen was my downloads drop as expected, but eventually I started getting paid purchases. In regards to competition, I always look at how other similar apps to mine offer their apps. Most that I find now are the free ones with in app purchases, the free ones, and the paid ones with no in app purchases. I do see a few that are paid and also have in app purchases. Hope this helps!