This is a bit disappointing, and I think will ultimately work to Blynk's disadvantage.
Previous to Blynk I've been using TouchOSC to control things from my iPhone, it has a one off cost of $5.00.
Now I have Blynk, which is mostly better than TouchOSC, but it is going to cost me $25 in the first year. I would hope my projects would last 10 years, so that would add up to$250.
Ok I'll build several projects other 10 years, so the cost gets spread a bit, but if someone wants to copy one of my projects they get hit with a $250 cost and they may not use Blynk for anything else.
And for the money I get access to an online server that I'll never user and an every increasing bunch of widgets of which I would only use a handful.
Given a yearly subscription I think a lot of people will not bother with Blynk, it is no fun when you loose control of your project because you forgot to pay your subscription.
TouchOSC may not be as fancy, but it will end up being a lot cheaper and less hassle.
I feel it would have been better to have a one of fixed price of the app, extra cost per widget and a subscription to use the online server.