This EIP is just one of many EIPs that would benefit from a new transaction type. Some other examples include EIP-1559, Rich Transactions, Multisig transactions, etc. At the moment, we have to be very careful that all transactions are uniquely identifiable based on the number of arguments they have. The idea with EIP-2718 is that we can solve this problem once and then going forward all we have to worry about is not re-using the TransactionType number, but we don’t have to worry about overlap between types otherwise.
Note: We should continue this particular conversation over at EIP-2718: Typed Transaction Envelope 