The amount of capital they need to raise, despite the claimed revenue, indicates that they spend more than they gain, which is by definition unprofitable.
Well ArchLinux has a product for you if you want packages that were vetted: the official repositories.
AUR is just a centralized place to put user created packages, like npm is a place to put user created node packages.
Sadly this does not seem to be the case here: if you read the announcement entirely, they include a "cost per task" metric which basically continues the trend of their previous models. So yes, tasks will cost you more, but results will be better - allegedly.
Strange rant. From a user perspective, it is very handy to have a very simple text format in which you can occasionally insert complex mathematical expressions. And at the same time, it's perfectly okay for most implementations to NOT support this syntax