Yes, you are adding more layers to the cake, so more potential points of failure. But, if you do it right then you are actually creating more resilience.
With a Blynk only cloud system, if the Blynk server, your internet connection or some piece of infrastructure in between fails then you have no control over your device - except possibly if you’ve incorporated physical controls and don’t use a blocking connection method.
My HA system can still be used if any of these things fail.
This infrastructure setup also allows very simple integration with other services such as Alexa, and to integrate other communication systems such as LoRa, IR, 433MHz.
I love using Blynk as my front-end, but having Node-Red as my logic/rules engine is such a powerful system. Many of the minor changes that I make to the functionality and interaction of devices is done via Node-Red, without the need to make firmware changes.
Pete.