As you can see the answer to this question is above.
Unfortunately it seems as though the OP made a mistake and SF is not in Miami, it's the other way around
It seemed a little weird that SF would be staying in Youngstown for the 3rd time since last season, but since they have been doing it recently it had some merit for sure.
To answer Deb's question---the Youngstown, OH connection is there due to the DeBartlo's having so many ties, buildings, organizations, power/money etc in that area since that's where they started their ownership etc. Having that kind of "at-home" quality goes a long way since many strings can be pulled for the best of everything, optimal practice sessions, etc.
Denise DeBartlo York is the sister of Eddie, who was the owner of the SF team through the SB years. I am not sure about the circumstances but the NFL made him give up his ownership (in theory) due to some sort of breaking the law. Either that or he simply signed it off to her due to tax purposes or some white collar problems, but many have said that Eddie still has ties to the team that aren't just through his sister and her husband.
Mostly though it is due to the fact that traveling back to the West coast wouldn't have made much sense since SF had back to back east coast games 2 years in a row. I believe they would certainly be doing it again if/when that back to back east coast schedule hits again in a couple/few years down the line.