I was initially afraid this app could take a turn for the worse and become used mostly for "less respectable" activities, but what I have actually seen are (in maybe 30% of total users) small businesses (like hair stylists, landscapers, and other one-person companies without a main office) looking for a cheap/easy way to not give out their personal phone number.

The other main use case I see (about 10% of total users) are international (non-US) users, presumably to make/receive calls with US-based people without incurring international or long-distance charges.