I can do that because I have no social life and everything is optimized so that I can work all the time. But I don't think I would recommend that to everyone.
Benefits are :
* You are never bored
* If one of your job annoys you, you can always balance with the other one
* You have a lot of money, because you have two salaries, but you also don't have the time to buy anything
* And you dont waste time on useless things
Disadvantages:
* No social life
* No time with familly
* No leisures
* Very tired all the time
Honestly having a startup is usually not only something you can focus on only the night, you need to answer clients during the day, you need to monitor everything all the time. But if you love working, this is definitely something that you can enjoy