How can Bitcoin Cash be used as cash if I have to wait 10 minutes or more for a confirmation?
With Bitcoin Cash you do not have to wait for a confirmation for the vast majority of transactions.
Bitcoin Cash transactions are confirmed in blocks of transactions that get added to the blockchain every ten minutes, on average. When a transaction is confirmed in a block, it is proof that a significant amount of energy has been expended to include that transaction. This is a process called Proof-of-Work (PoW).
Much more energy would be needed to reverse the transaction. The energy required to reverse an already-confirmed transaction can always be used much more profitably to simply extend the blockchain further, rather than reversing previous transactions. That makes the reversal of transactions that have already been confirmed extremely unlikely.
What sets Bitcoin Cash apart from other coins is its dedication to scaling. Because of that dedication there is almost always plenty of room for transactions to be included in the next block. That is different from many other cryptocurrencies, including BTC, that are congested and require transactions to compete and pay inordinate fees to be included in the next block.
Thus every transaction on Bitcoin Cash is nearly guaranteed to be included in the next block. This gives Bitcoin Cash something called zero-confirmation (0-conf) security. It basically means that a transaction that gets broadcasted across the network is nearly as good as a confirmed transaction.
0-conf security is definitely not absolute. It is technically possible for a miner (or someone colluding with a miner) to stealthily double-spend a transaction. But such schemes are essentially only profitable with very large amounts. Therefore, any transaction worth less than $1000 USD, for example (and possibly much more than that), should be just fine to accept without any confirmations (note: set your own 0-conf policies based on your own business model and risk profile).
Of course any business or exchange is free to set its own 0-conf policies. Some exchanges require multiple confirmations before crediting deposited amounts. However, not all businesses or exchanges base their policies off of actual risk or hard data.