We have this in Jerusalem.
At busy times the van takes up to around 6 people and at quiet times you're by yourself.
At busy times your ride can take up to triple what it would have taken otherwise, because it makes stops for other people. Like 45 mins instead of 15, which makes it pretty unpredictable.
You also often have to wait a while for it.
They're called TikTak here.
It's mainly useful for getting a direct ride where you'd otherwise have to take more than one bus.