That's really interesting. In a sense, you can go direct, but the product can save other designers and agencies lots of time. If the client is happy with the results does it matter how the sausage is made as long as they are paying a logo fee and not for fraudulently claimed hours worked?

That time they could save is likely much more valuable than just the one time fee, and constant improvements and features for them could very well justify a nice recurring subscription fee.