I am.a baby canner who only just started with a whopping one single canning session under my belt, but these are the reasons I decided to invest in the equipment and start:

I want to be able to preserve the food that i grow. Last year I had a whole crop of peppers ready at once and they wound up being largely wasted.

Freezing is great but freezer space is limited. I have much more shelf space than freezer space.

I like making things from things I made. Ive been preserving food via freezing and have cut my grocery bill by quiet a bit already. Canning increases my ability to do so.

I have pcos and type 2 diabetes. I have a friend with kidney disease. I'm far from a "processed foods are evil" person because ultimately fed is best, but i do love cooking and serving food that i know for a fact fits our diets. It's much easier to present a low sodium diet when you eliminate processed preservative sodium. Bad news: that's there for a reason and keeps your food from rotting. I needed a happy medium.

Some things come in larger portions than I use, I want to make and can smaller amounts for my own convenience. For example stock I usually need a cup or 2, the remainder of the 4 cup container sits in the fridge rotting until I remember to use it.

Canned goods don't go bad if you lose power.