The TSA have 3-4 specific ‘TSA keys’ (which are easily purchased), and they demand you use a ‘TSA approved’ lock which has an extra keyway explicitly for them to use. If you don’t use one of these locks, they’ll cut yours off during inspection and give it back to you in pieces, with no compensation.
There are universal luggage keys because luggage makers make locks that need to be opened by 3rd parties. Barrel locks aren’t designed that way.
Also the TSA has a set of universal keys, there isn’t a single key that works on all luggage.
The TSA have 3-4 specific ‘TSA keys’ (which are easily purchased), and they demand you use a ‘TSA approved’ lock which has an extra keyway explicitly for them to use. If you don’t use one of these locks, they’ll cut yours off during inspection and give it back to you in pieces, with no compensation.