For me it isn't because my DD has a very definate taste preference. HOWEVER, it is a good skill to know and can lead to other, more cost effective menu options. For instance, I haven't yet perfected my pizza crust recipe which is basically like making my own bread. Making my own pizza crust would result in a HUGE cost savings for me, if I could only end up with a product that I really like.
It is unfair to compare homemade bread to the cheapest bread in the stores. The cheapest commercial bread available is nothing like homemade bread. Instead we need to compare the homemade stuff to the specialty breads that we would tend to buy.
And it is nice to be able to make specialty breads for special occasions with some consistency, too. There are a whole host of inexpensive menu ideas that come to mind that use bread and a bit of leftover meat and veggies as the main ingredients.
Lastly, making my own bread could lead to stretching the budget just a bit, especially when there isn't cash for running to the store. Basic bread is nothing more than flour, water and a little yeast. With a little pre-planning I could make rolls for hamburger buns instead have to run to the store. That would be nice.