Making bread on a flat surface allows you to minimize costs of entry (not only don't you need the forms which are relatively cheap, you can go with simpler/cheaper ovens), and this kind of bread has a more pronounced crust, which many people like.

Crusts like this generally require a lot of steam in the oven, and steam ovens are usually much more expensive than non-steam ovens.

If you want a homemade loaf that can actually produce the type of bubbly crust you expect in certain types of European style breads, you'll have to trap a lot of steam where you're baking it, often by containing it in a Dutch oven.

And shaping/forming a loaf that stays tall when being baked on a flat surface takes skill, lots of practice and experience.