I've never smoked sausages (indirect heat) at higher temps. I've grilled hot & fast, and smoked (indirect) low & slow. The most recent sausages I smoked were breakfast links, and even those casings had a nice snap. I find that hot & fast grilling produces the toughest casings, partially due to searing them, which also sears the meat just under the casing. As for higher indirect heat, I would think that at some point a tougher exterior texture would be the result, but not so much if you don't overcook them.
If higher temps work to your preference, then, roll with it, but, low & slow has worked fine for me in the past.