Commerce Zero Downtime

Hi,

I am looking into the process of having zero downtime.

In the documentation I see that when deploying we can have 2 different database modes ReadOnly and ReadWrite.

I wish to use the ReadOnly mode (recommended), what isn't clear from the documentation is how this effects a commerce site.

I presume customers can still add to cart, update cart, add billing and shipping address, process and order.

Would that assumption be correct?

Thanks

Paul