Plenty of reasons. To prevent media pressure on Buttler's place in the team, confidence boost for the lad, vindication of management teams decisions.
Crawley scored 250 and a 50, Buttler scored 150 and a 50. And there were questions about his keeping throughout the summer - let's not forget that awful day he had dropping 4 catches in a day. Also Crawley is in his first proper test series, Buttler must be up around 60 tests now, so all of that factored in, can you really give a reason why Buttler deserved it more than Crawley?
Yes, it was a good catch. He did drop several pretty easy catches as well though to counter balance.
Deadly serious mate. Not sure why Crawley would not win it ahead of Buttler aside from England management intervention