I think this section justifies the implicated recency:
"The corresponding research paper [...] will be presented at the 20th Privacy Enhancing Technologies Symposium (PETS 2020) on 14-18 July 2020 in Montreal, Canada."
This German site [1] had an article on the bare cost AppGratis asked the developers to pay:
In Germany you pay 15.400€ for a slot.
They work on a CPI basis. The CPI rate is 1,1 euro for iPhone and 2.2 for iPad. They list the amount of downloads that they "generally can achieve in Germany, Austria and Switzerland"
It's more ment to save you the time, typing a list of 100+ app-names. I'm not afraid of talking to friends. But when I met them, i'd rather won't use the valuable time to talk them through a huge list of iPhone applications.