I think they will practice until they get the landing right all the time.
The engines with vacuum optimized nozzles are not suited for landing. They can not be gimbaled and are very over-expanded as well. I would not be surprised if the engines with vacuum nozzles destroyed themselves if they were fired at sea-level.
You don't want them running for long on full power, but it's probably OK to use them for slowing down an emergency landing if the sea-level engines become otherwise unavailable. The alternative, as we (and SN10) saw with SN8 and SN9 is not great.
