It checks for the validity of an address. A valid Bitcoin address is also a valid Omnilayer address.
I think something can be done, in a way to invalidate tether omini addresses while mistaken for bitcoin addresses. All needed is a little more of programming and testing.
If we remember the litecoin nested segwit addresses that started with 3, people also mistake it with bitcoin and has resulyed to many bitcoin been trapped and lost, but litecoin developers was able to create the M-ptefix version of the address with the same private key as the 3-prefix. That aside, also the address is not valid while mistaken for bitcoin address (although, I read this, not yet in my practical).
I am not certain, but I think there is something developers can do to make this work. Although, I used litecoin as an example, but not a perfect example though, but when not yet implemented, it can make people think such many not be possible.
You cannot change the address format of an Omnilayer address. A valid OmniLayer address has to be a Bitcoin address; the transactions are being done on the Bitcoin Blockchain itself. If the address isn't a Bitcoin address, then the transaction wouldn't work.
You cannot compare altcoins with Omni. Alt coins runs on completely different network while an OmniLayer has to piggyback on an existing coin's blockchain.