Blanching is beneficial because it can help prevent browning, plus it will denature and destroy enzymes, and it can reduce acidity a little bit. That will help in sausage making, but the downside is that it can affect or damage texture or flavor a bit. While it can damage the flavor or texture, it can still protect flavor if you are freezing some fruits/veggies because freezing can do even more damage to flavor/texture.
If you reduce the acidity, and denature or destroy enzymes, it will help in your meat binding. Getting rid of some of that acidity and the enzymes will help the meat hold, stick, and bind properly to the fruit/veggies.
Hopefully that helps explain a bit more. Let me know if you need anything else!