To be honest, using VR for a meltdown may be quite interesting for some, for example, those that tend to try to escape and find a quiet, safe space to calm down and rest but have a hard time finding one - VR definitely has a possibility to provide something of similar characteristics. However, the problem is the size of the VR headsets at the moment - as mentioned, they are bulky and annoying to transport.
There is some potential but VR sets themselves would have to become much smaller, pocket versions and made from sensory-friendly materials, as well as having enough noise insulation like some of the high-quality headphones. A small device like this, something you could use similarly to glasses, just sit down, cut yourself off and relax/calm down, may be useful.
Maybe it could have some calming sounds included like rain or cicadas? Some visual input with a choice of place, some with dimmed light like a room with a candle, or fully dark like a night sky with/without a campfire, or just relaxing places like a forest or a beach. Maybe headset could have an outside texture of some kind that could be customised (wood or stone for me, they are really relaxing).
Outside the whole business of let's-get-money-from-people-with-problems, it does sound quite interesting as a relaxation tool.