The odds state the truth here. Milan is more superior compared to Venezia. They have better quality players, a better coach, and also a home game. With all of these aspects, I'd bet on Milan. But it must be noted that the risk is not worthy enough with the odds.

Milan is far better than Venezia. But, they are underperforming now. They can come with a surprise to us.
Odds show the team that has a greater chance of winning. Milan is definitely the favorite, you can bet on that. But as you mentioned, Venezia might surprise. Not because Milan is playing at home. But because they are still not stable enough in their performance.
Venezia managed to hold Fiorentina to a goalless draw at Fiorentina's home. Their levels are certainly different, but that shows that there is nothing certain in the odds offered. Milan cannot underestimate Venezia.
The odd of Milan in this game is showing that they have a good chance of winning and since they are playing at home I don't think they would want to miss the chances of getting 3 points unless the Milan coach Fonseca wants to lose the trust that the fans have for him because they didn't start well this season. Venezia was very good in defense against Fiorentina I think playing against a team like Milan they will have a lot of work to do because Milan will definitely want to counter them until they are able to score goals to win the game, Milan already knows what they should expect from a team that played draw against Fiorentina they can not underestimate them unless they want to be defeated at home.