I think what he means is rather than lose even more money on the beamer on his drive, trading it in for this one is damage limitation, cutting his losses. This may not be the best car he's bought but he's getting more cash from the trade in of the white BMW than he will get elsewhere by trade in or selling
With the silver BM you might not get all the toys or the looks of a white M sport but for a daily driver it's a nice drive, comfy place to be and a bit more poke. I'd rather have that as a shed than some of the trash Iv seen on here
If you can't get more money for the beamer any other way then go for it