these tag bits are often used for the GC and there you really don't want to collect all of the tag data together since it would cause false sharing issues
It's not for unrelated values though. Actually, the real observation is that tags aren't useful once you have a value, they're useful to get to the value in the first place.
In a stack frame, all the local variables have their tags together.
For the fields of an object, all the tags are stored together in the object.
