Continuing the discussion from Filtering JSON export:
GRAMPS: 5.2.1
Python: 3.10.12
BSDDB: 6.2.9 (5, 3, 28)
sqlite: 3.37.2 (2.6.0)
LANG: en_US.UTF-8
OS: Linux
Distribution: 6.5.0-28-generic
Looks like the issue is still actual. One of possible cases where the plugin can be used is for graphs building and visual relations researching How to make visual research of a person/people with with their associations? - #31 by Urchello
And working filters are really needed there.