It's because they need to distinguish it from the gambling name. Betsson provides gambling services and it's not allowed to advertise them in Italy. That's why there's the .sport suffix. Which is kinda ridiculous because you can still see the Betsson there, you go and google it and you find Betsson site and their gambling services.
Even the "betsson.sport" URL directs to the betsson.com main page with the gambling links etc.
But it is what it is and most probably club took the highest offer and we pay it here with the shittier sponsor text/logo.