I agree that following browser default behavior is more intuitive in general. I'm not a fan of scroll jacking. I'd say apps skew towards mouse-heavy because co

I agree that following browser default behavior is more intuitive in general. I'm not a fan of scroll jacking. I'd say apps skew towards mouse-heavy because controls are on-screen and therefore discoverable. It takes a good deal of product-market fit before you can count on your users knowing/caring enough about your app to remember keyboard shortcuts. Most apps are grown by adding users, so optimizing for the new user is more important to the business until a certain level of maturity and market saturation is reached. Applications with a dedicated professional user base can go deeper into power-user territory sooner since they can charge more per user, and new users expect there to be a learning curve.