I have been watching Runa from the very debut, same with her other genmates. I admit at first I wasn't sure if I would like her, but her tiny bit of 'tism at the start and general anxiety of being around people, on top of her actually dedicating herself to play a character and do such impressive voice and mannerisms make me think her and Miko are the best HoloJPs, but that's just my opinion.
Whenever I watch Luna, I can always shut off my mind and pretend that everything is okay. I am really happy that she is, just like us, despite being the cutest candy princess, is also a human with her own tiny flaws.
If i have to say for short, I watch Luna because watching Luna is like watching your cute daughter grow, and Miko is the cutest little sister that you will never take seriously, just want to do nothing but feed her snacks. These chubas unlock big mother/sister instincs in me, and they are the only JPs i still watch, and I am only 21.