Tail emissions is the least of it. They enable variable block size so you can do bank runs on custodians. 

Don't get me wrong, I'm not here to shill monero. I'm saying that what Bitcoin needs is going to change as it gains adoption to ensure it continues to freedom money. Maybe being vulnerable to takeover of custodians is the carrot that banks and nation states need to adopt Bitcoin and win the NGU race. Once it absorbs a significant amount of the global capital gains will diminish. It then needs to compete with cheaper, faster, more private coins that have growth potential to take market share off Bitcoin. This is when it will be important that Bitcoin has smart people making improvements to remain dominant and resist capture from banks who can offer economy of scale services but not really offering the real freedom of Bitcoin.