Yes, but San Marzano tomatoes that are sweeter are still only 3g of sugar per 100g, and 2g of net carbs per 100g.
And if you make a mirepoix for your sauce, the sugars in onions and carrots are higher.
So for people that are afraid of sugar, a sauce made with tomatoes, carrots, onions and celery isn’t as scary as adding sugar.
And the acidity isn’t considered as well. From experience, they are less acidic as well, so you don’t need to add sugar to mask that.
They tend to be less acidic and a bit more sweet. If you use a mirepoix and San Marzano tomatoes, it contains all the sugar you need, and the total net carb is still low.