It depends what you are going for I think. Igbo your goal is to loose weight than a longer session will burn calories fast, Just don’t refuel lost calories in a weight loss program. However if you’re goal may just to fill up time or you are bored than over a period of a day of regular excision is good hood!
It really depends on your preferences. If you feel like you can't do 1 hour long exercise then it's ok to break it down to a few shorter exercises during the day. It also depends if you have time during the day for these smaller exercises. For me it's better to do one longer session because then I don't have time during the day.
I like to do short sessions because it is easier to do that that because you're not restricting yourself a impossible goal.