Let's see. Homeless: I have family members that will take me in and when I'm living with them I could get a job, I also have freedom. Jail: I have to worry about whether I'll live or die everyday, no freedom, garbage food, and just about everything else is bad.
In jail you have 24hour security, lifetime acomodations, food at every meal, people to talk with, you have a walk everyday (if you're not too bad), you have showers (even if sometimes it's better not to...), you have laundry, you have a safe place to sleep (if nobody shares your room). And everything you had with you when coming in jail is keep in a safe and give back to you at the end. Whereas when you are homeless you just have people to talk with and you have to leave your place when the police is coming.
I suppose you haven't heard of the frequent prison riots, prison ****, and the bullying that goes on behind those bars....
And jail is nothing like what it is on TV and the movies, I know some Ex-marines who got in a fight in a pub, one of them punched a guy to hard and he died of brain damage; they ended up in jail, and it isn't all that bad.
