I don’t see why not, as long as everything meshes properly… I do know that many basic serial based links have issues, because they expect to have 100% of the devices time, listening for a possible incoming data byte… one that could be missed while the sketch is doing something else like processing a App command.
Well, it does maintain the “housekeeping”… I believe other stuff is automatically processed… but it is not adding delay for delays sake.
The issue is usually that other basic Arduino sketches tend to sit in the void loop()
and run as fast as they can because that is all they do. But Blynk adds in a timing sensitive server based communications link to the App, and if the other programs are not correled properly (often needing to be reformatted and set into timed functions, usually via Blynk Timer) they will overrun and/or delay the timing needed to keep Blynk connected.