If BTC is the most valuable asset in the world and inflation continues as it probs will  they may come just for the sats alone. Although zaps are now easy for any fiat app to integrate now as well with things like NDK. 

"The question is what app(s) can be built on Nostr that are significantly better than current products available in the world. Not just a little better, not just 10 times better for freedom-minded folks, but 10 times better for a large population of people that are already paying for something similar. It’s a tough question and if there were any easy answers I’m sure they’d be built and profitable already." 

 That could be the case! But if Bitcoin value increases as denominated in fiat then I’d imagine people will zap smaller amounts. People with Bitcoin will see the value of their current stacks grow but it’s hard for me to imagine folks zapping large amounts after the surge in value.