I flew Delta about 6 months ago and they had something similar, also for free, but they use Viasat. I think most of the big airlines were moving this way anyway to be honest, Starlink just has a good opportunity for advertising.
Starlink speed and bandwidth is way ahead of any of the existing satellite internet providers.
I believe Viasat internet satellites are placed in geostationary orbit, whereas SpaceX Starlink is not, so the service Viasat provides is already blown out.
Long latency makes Viasat good for some things and not so good for others.