It was a convenient platform where a lot of people were. It's also where a lot of people went to complain if they were having issues with the regular support ch

It was a convenient platform where a lot of people were. It's also where a lot of people went to complain if they were having issues with the regular support channels so of course companies would go there to perform damage control and act as a kind of level 2 support channel where issues with the normal support would be voiced. Also doing it in a quasi public channel is a bit of PR advertising "we look after our customers" even if it's only partially true given they had to take to twitter to start with.