Even if it is “allowed” that doesn’t mean it’s a good idea or that it could be the beginning of a slippery slope. Has any other pope done this before in the history of the Church? I’m not aware of any.
And who’s to decide if it’s a “good idea” or not? A couple of Internet theologians or the Pope himself?
Funny, as a Catholic I think the latter is more qualified to make that judgement.
Francis is doing a lot of “firsts”. He thinks he’s a trendsetter and the secular world loves him for it.