@rohitRoy Based on what I see and understand… Blynk makes a development system for IoT development and personal use… it consists of the closed source App, open source Library and Cloud Server access (or optional Local Server)
It is low cost with App energy sales to help offset Cloud Server costs and overall development, or even free with the extra effort of setting up your own Local Server… but this is for personal use and pre-commercial development only.
Obviously they have a business side that actually pays the bills and thus they do not want to give the whole cow away for free So if you have need to make money using their system, you will need to licence it… and they will make a custom App that fits your needs perfectly.
As for why someone would want to pay another 3rd party Cloud Service every month and install Blynk’s free server on it, instead of paying much less for recyclable energy and using Blynk own Cloud Server… or just using the more common method of installing Local Server on their own RPi, PC or Linux box… who knows??.. People are strange