There’s more at issue than the technical concerns:
Licensing
The free Spotify user agreement specifically limits use to “personal”. Using it for background/break music on paying gigs puts you in violation of the contract you signed to enable use of the free app.
OTOH, if you pay for Spotify you’re covered for such use…AND you can simply download all the music you need and not have to depend on the WiFi du jour for a likely iffy connection, so being a responsible, legally licensed user obviates the technical hassles.