The point is not in WiFi but in connection to the server: your device have to be able to talk to blynk server. The simplest option is to have your device connecting to the ‘Blynk Cloud’ server via internet - it is already there and maintained for you. Another option - install and maintain your own local server.
If you insist on omitting blynk server, the only option is to use bluetooth module for direct communication. Direct communication via device’s WiFi is not supported.