When filtering in HA you can choose to include null values ON TOP of the value you’re filtering by, e.g. 
 

This is very useful for treating 0 and null values as the same (when you need to); 
 

However the same filtering option isn’t possible in Rules Engine, if you tick Null then it overrides the value you choose in the filter (by blanking out the value field).
 

The workaround is to put both statements in separately and OR them, but when we have complex filtering already this either becomes convoluted or end’s up being not possible due to the limit on number of filters allowed.
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Can we please bring the HA filter functionality over to rules :)