The multi-select feature is poorly designed throughout. In rules engine/query builder, we have to build overly convoluted queries to be able to track NULL values and combine them with (OR condition) includes/excludes.
It is also extremely difficult to leverage in any reporting considering the things we can or can’t do with it (can’t group by).
It’s impossible to write to it without convoluted formulas to not override what’s already there.
Everything about this feature is terrible. It needs an overhaul to start making sense and to stop requiring convoluted 20 steps approaches to get anywhere with it.