A sleep does you good
If it doesn't directly impact your ability to sleep at night then that's a good thing although I realise some do have their sleep disturbed because of this. I think people in the Mediterranean have got it right sleeping in the early hours of the afternoon and opening up in the evening feeling refreshed. I know this is largely to do with the climate as it is cooler in the late afternoon/evening but it makes sense.
Sleep is important to everyone whether you choose to have a little siesta in the afternoon or at night and getting enough hours in helps the body and mind. If you have not had enough sleep and you work your performance whatever your job is sure to be affected. Whether your job is academic or manual your performance will not be as good I'm sure.
Some people think going to sleep in the afternoon for a while is lazy and they are entitled to that view however to me there is no harm in it. If you have worries or have a headache, for example, closing down for a while may alleviate those worries or headache symptoms.
Of course, not everyone will agree with what I have written here but I am just sharing what I believe.
To understand a siesta you must understand the climate. And heat with a full stomach makes you sleepy. @ze2000 @borderline @alex