It just reduces one of the many factors that could stop the deal from happening - mortgage contingencies. 

Former suburban dwelling millenials and empty nesters alike are finding the lifestyle in these areas very fun and desirable.Furthermore, the housing policies in these regions necessarily constrain stock (article from The Atlantic), so real estate is traded more like a precious metal than something manufactured. 

Also not sure about other factors.

Factor those in and I don't see any other reason why not.

Roofs maintain the integrity of the rest of the house and should be maintained as such.The price in which you purchase the property should factor in the age of the major mechanics along with windows, roofs, and siding considering where they recommend in their life cycle. 

Also, you will need to factor in the monthly condo fee that would need to be wrapped into your rental rate.If you are setting your price point based on a purchase in South Philly-just south of Washington Ave (which is adjacent to Center City proper) then you will be able to find many potential purchases for rentals here. 

Remember to factor in closing costs and realtor fees if you are flipping for full retail on the MLS.

I highly suggest factoring PM in even if you're doing it yourself.

You also need to consider your income when factoring financing.

It depends on a lot of factors including price, time and interest barriers, property availability etc.