Anticonsumption

Yes, it's a flowering plant. The fruit look like tomatoes but are poisonous. But sowing seeds has some disadvantages for potatoes.

First, unless you take precautions the plants you grow will cross with others around, you'll end up with a mish mash of variety characteristics in the progeny. Maybe good, maybe bad.

Second, any tubers your sown seeds make in the first year will be tiny, it might take several years of keeping tubers and replanting before you get anything worth eating.

So unless you're experimenting it's more productive to not eat a few tubers and replant them for the next years crop. More consistent flavour and a bigger crop.