The cool thing about Voyager is that it has a record of information about Earth, etched in gold, with instructions on how to read the data it contains back.
Even once it powers down, it's still on a mission. If millions of years from now intelligent alien life ever encounters it, they will know who we were and that we existed.
It's our handprint on the cosmic wall.
IMO this is mainly a way to communicate talking points to his supporters. They want to start a lot of talk about Biden's "election Interference" to make it feel like this is something both sides do but only Trump is getting charged for.