I think it's just funny and maybe the captain wanted to make a joke. I had flights with very nice crews in the good old DBA times and they sometimes made also some jokes.

In that time it was e.g. something about very dark and black clouds which they had to avoid and thereby getting a delay of some minutes (but didn't remember the exact phrasing).

Maybe in such a way they avoid the daily routine of short-haul flights. So if it's just fun, it's ok. AND very professional due to helping everyone to concentrate on the flight.