I think it's a hangover from the French pronunciation, without an H. We have put the H in the similarly-derived words: hospitality, hospital etc.
I think those saying 'an hotel' would probably have the French pronunciation in mind. I do think either is acceptable.
Of course language evolves. I have begun to say 'stadiums' instead of 'stadia' because it is less understood and sounds odd. Interestingly, we rarely use 'datum' but have taken 'data' into general use.
Air Conditioning units ,any advice please?
I Shall Be a Weather Forecaster In My Next Life Or...
What to do when you are not needed for childcare as they get older



