Coinbase did something good with this announcement and I'm sure in the future other exchanges will follow that will implement the lightning network in transactions like them.
While its of course a good thing when one of the biggest and most popular exchanges announce LN integration, there are many exchanges that are already supporting LN so Coinbase is not doing anything that others haven't done before (and some of them like Bitstamp implemented it years ago). Here you can see the full list of exchanges with their current situation regarding Lightning Network.
