Blynk expects a constant connection to the Blynk server, with Blynk.run being executed at least once in every cycle of the void loop (which needs to not be delayed by blocking code or a cluttered void loop, so that it can execute hundreds if not thousands of times per second).
The strategy for handling a situation where you still want additional processing to continue uninterrupted when the connection to the Blynk server is down requires the approach we discussed above.
If for some reason you are trying to reduce internet traffic, and only connect to Blynk occasionally to send updates, then go offline, then a different approach is required.
However, f you do this then BLYNK_WRITE(vPin) callbacks won’t function as expected, and dome additional coding, such as the use of the BLYNK_CONNECTED() callback and the Blynk.syncVirtual(vPin) command are required.
Pete.