I'm not even a frequent flyer, but I'd estimate that a good 80-90% of my Uber usage is travel-related. At home, I have tons of other options to get around, but on a tight schedule in an unfamiliar city, I basically default to Uber all the time, because I rarely have the time or risk tolerance explore alternatives.
One of the things I love about Uber is that I can use it in SF, Singapore, Manila, Helsinki, wherever. It also works sufficiently well that I have near-zero incentive to try out Lyft/Grab/Ola/whatever, particularly since this usually involves yet another tedious sign-up process of entering credit cards and PIN confirmations and yadda yadda.