I imagine it’s the same as UHT/long life milk - they use heat and pressure to preserve the contents, which is why there are no additional ingredients to what’s listed. Legally I don’t believe they could not list something that’s in them. When my LO was first starting solids, I would use them on occasion for emergencies and out and about scenarios. For me personally it was unrealistic to be able to provide home cooked purées at all times. I actually used a baby food services and had a delivery of frozen purées every couple of weeks which was great as they were only raw ingredients and snap frozen. Eventually it becomes easier to feed them once they move onto more whole foods that don’t need to be blended/textured, I found!
Also I should add, if you plan to travel internationally / by flight the pouches are great as they’re shelf stable and you can take them through customs etc.
I was told they are full of sugars even though technically healthy. They have lots of fruit in usually and baby loves that taste so will get addicted them and eat less food at home (only what I have been told though). I think it's better to cook from scratch and use those if needed, like on the road or something. Just blend a bit of your own dinner, don't think it has to be fancy!