You just get the information you need way quicker.
Recently I had to make changes to cancel my flight. Luckily the website had an agent and I used it to cancel my flight. Didn't have to wait for an email/chat or worse call.
I even rescheduled my flight using the same website agent.
It's just way more convenient.
Airlines websites could be so much simpler and quick to use if they weren't designed to be full of traps.
Don't expect that edge to persist indefinitely, they are in the adoption phase.
Great if grandma doesnt know how to use a web form, fucking useless for everyone else.