As the number of website visitors and shoppers grows on mobile, it’s important to consider how small additions to your design will encourage them to do more than just research and browse. One of the elements I think mobile designers — for PWAs and mobile websites — need to do more with is the sticky bar. What exactly do I mean by “more”? Well, I mean using the fixed navigation bar at the top or bottom of a mobile site for more than just navigation or branding.

https://www.smashingmagazine.com/2020/01/mobile-pwa-sticky-bars-elements/