I think it's complicated. 90% efficacy against with strains, for how long?

And isn't the whole point of vaccines preventing people from developing severe symptomps and dying?

The whole point is to not stress the medical institutions. There still will be people that has been fully vaccinated, got covid, and get treated in the hospital, but ideally there should be a few of them, unlike what happened in China with patients sleeping on the floor in the ward because of overcrowding.

Covid is an ongoing topic, so we shouldn't see any claims as permanently correct. No one can predict what's the next dominant strain will be, and whether the current vaccine is able to protect against them.