I too struggle with the cost, but have purchased and used. Didn’t seem to run into any problems with the sanitary issues some suggest. I also have a pressure cooker that I do can Wort from time to time. A few things prevent me from always making starter Wort and canning:
1. It uses up time that could be spent on other brewing activities. One pressure cooker full of jars doesn’t seem like enough so I want to do multiple batches in th pressure cooker.
2. When I make starter Wort from DME I end up with a fair amount of hot break in the mason jar and that I feel I should filter.
3. Feels like forever to get the DME to dissolve in the mason jar before it goes in the canner.
4. Lastly, the pressure cooker makes my wife nervous!
I don’t have a strong opinion on making vs. buying starter Wort and could probably be convinced of the merits of both within the same conversation.