It’s the only “ending” for their characters in the film. And it’s assumed this story thread will come back again? Possibly pick up in the Lando TV show they announced, perhaps? So, might as well just keep it.
Neither character is really all that important to this film though - do we care if they get an ending here? I’m not fussed about Rose and Babu Frik getting all but ignored in the final scene and both of them arguably did more in this trilogy.
But while we’re on the topic of the ending, maybe cut Chewie getting the medal? It’s so fan-service-y and embarrassing.