An industry point of view;
* I have some, they will actually hold more than the rated volume and you can squeeze the bag to create the shape you want.
* they are extremely useful in a winery for holding wine which us used for topping off.
* you specify short term instead of long term, retail packages will have a two year best by date. I have used them as a variable capacity second racking carboy, it works, but you need to be careful racking off the fine lees, The spout which is welded onto the plastic takes a standard glass carboy cork, the spout needs to be supported if you fit an air lock.
* I like metalized film as an extremely low oxygen transmission container. The clear EvOH bags are made up of multiple layers which create resistance to alcohol/ oxygen/ meltable spout sealing surface/ temperature resistant stretch/ visibility racking off lees.
* they are food grade, they are UN approved for emergency stockpiles of foods, they have a lower footprint than metal or glass, ,,, AND cost less
* compared to glass they look cheap but in retail packaging have neat features as a silicate layer is transparent and a retort temperature barrier so one can have printed product graphics as well as see what is inside the pouch
* a typical wine bag needs to be protected from punctures. Some of the UN approved grade will stand by themselves.
* retail adaptations are out so one can carry wine in a shoulder bag to the picnic
* cleaning/ reusing isn’t the best, they have a seam or a gusset which you can’t get at. I wash as with one step, rinse with water a few times and then rinse/ store with an ounce of grain alcohol
* the spout is never in a corner, it is always welded onto a flat surface
“Family wine” has been an issue for centuries. Old Italian technology would be a ceramic crock with a spout, a round board floating on the crock and olive oil layered on top for a flexible oxygen barrier. Bottles with corks are relatively modern. My guess is great grandpa scratched his head and asked if something as expensive as glass was worth it.
You will find more products in multi wall plastics in the future, they work.