I think the big issue is those have an internal CO2 cart that can not be replaced, same for Heineken. (They are all a little different.) The mini-kegs that have That have the pull out spout on the bottom and a tab on the top (usually red) can be reused.
The biggest issue is these are made of steel/tin and will rust. There is also a a bag inside that once compromised makes it unrefillable. Midwest sells new ones and it seems to be 5-11 refills before failure.