Some ULR layovers are 48 hours, many are 24. Almost all the non-ULR layovers are 24 as most of the places we fly to have at least a daily service. Remember the 24 hours is from scheduled arrival to scheduled departure. A typical timeline for a 24 hour layover is something like this:
00:00 On chocks.
00:45 Off aircraft, into queue for immigration
01:15 Through immigration, waiting for bags (crew bags are not always the first ones off)
01:45 Through customs. Can take much, much longer if some genius has decided to smuggle a banana into Australia
02:00 Bus departs for hotel
03:15 Bus arrives at hotel
04:00 Finally have room key in your hand. Layover starts!
This process is repeated at the other end of the layover when the pickup from the hotel is typically about 3 or 4 hours before departure.
So, your 24 hour layover typically has 4 hours removed at each end, assuming you actually arrive on time, and is actually about 16 hours. Obviously you need to sleep for about 8 or 9 of those hours (you probably left Dubai at 2am) so realistically you probably have about 7 or 8 hours per layover to "see the world."
If your aim in life is to travel, see new places and meet new people this is not the job for you. You will only achieve the first (and maybe third) of those. You will see a lot of airports.
On the plus side, most of the hotels are pretty good and some are very good although locations can vary greatly from central downtown to airport.