Heat is infrared. Light. Vacuum doesn't have much effect.
Also many bulbs are filled with inert gases rather than being vacuums.
I'm guessing part of why Apollo took a spotlight was the dev being very open in how he was trying to negotiate with reddit and how spez tried to smear Apollo with lies about blackmail.
I never used Apollo, but it's pretty clear the dev loves making it, and is very communicative with it's community. Which is great.
The official app is hot garbage.
I've got a cat (indoor only) who's normally a lovely little guy who love pets and cuddles. The occasions he slips outside he becomes a rage monster and it often involves getting mauled to catch him and get him back inside.
Being outside their normal space can make cats anxious, anxiety makes affection unwanted. She's concerned her idiot humans will get hurt/lost and she's being vigilant for threats.