A periodic, full muster drill is probably more about keeping the crew 'current' rather than passengers.
Safety is all about risk and ensuring that the right things happen consistently to mitigate those risks. As passengers, we are on the ship for a very small amount of time and our responses in an emergency are highly likely to be random. Crew, however, are onboard for long periods of time and, therefore, their natural responses are likely to be far more influential.
The aim will be to get the crew's muster drill actions to be part of their 'muscle memory' so that they do it without thinking. The only way to achieve this is by repeated and regular practice.
As a passemger, the post COVID changes to muster drills make more sense and I think they are great!