Use a struct if the elements are related to the same thing.
With structs the first replication is the entire struct and its current element values. Subsequent updates only send values for elements that have changed.
Both struct and independent variables have roughly the same “weight”. Slightly larger on struct do to its structure… variables in a variable. The individual types will match up byte/bit to byte/bit.
Working with structs is more complex, requires more code to update/set. This will add weight to the class itself.