I mean we’re seeing what, maybe 10 minutes of her entire day? Her weekly vlog is like 40 minutes of footage covering the whole week-that’s hours and hours of their life cut down into tiny snippets. She’s obviously just picking random moments to film, same as he is. So when they both grab the camera, it’s for their own vlog, and naturally they end up showing totally different sides of the same reality
Dianne knows people love her parents so she’s showing more of them in hers, I think it would be weirder if Joe was also sat on their bed whilst she was filming the bits with her parents!! Joe and Dianne don’t go around their house 24/7 attached to the hip, I think they just choose to show different bits of their day- and it’s so little anyway that they definitely aren’t going to decide to grab their cameras at the same time and film the same things, that would be a bit pointless.