I see Top Zapper as an enticement for Zaps to help spread Zaps and to highlight that Zaps are the signal on Nostr. Remember, Damus had something similar, briefly, before Apple nuked Zaps. Top Zaps replies or comments were brought up to the top of a note thread I believe? Anyways, anything that developers can do from a user experience standpoint to make Zaps better or more front and center seems like a positive for me. Hopefully it promotes more Zapping as Zaps themselves have been slowing down.