Iride01 

The advantage for Di2 is not having to adjust anything. In the four years I've had my bike, the only time it required adjustment was when I went into the settings and mucked it up before I really understood what those settings did.

With my mechanical shifting, I'd be adjusting them at least once a year to maintain the perfect shifting I like. And changing cables every 2 or 3 years.

There are differences you'll experience with electronic shifting that are unique to it alone, but just things you have to get use too. I'm sure there were things I had to get use to with mechanical shifting too, but after most of a lifetime using them, I'd have to sit here most of the day to come up with what they are.

If this Venge with Di2 is fairly new to you, then you probably just need to get use to it and get some experience. If you are new to cycling, you might not be as good with the mechanical either as you now imagine you are when comparing it to the Di2.

I don't recommend converting the bike to mechanical. If you want mechanical, get a bike that has it already.