LANs effectively don’t exist. If you want to sell a speaker system useful to the general public, you’re going to have to deal with:
- Access points that don’t let WiFi devices talk to wired devices.
- Office networks that don’t repeat broadcast discovery traffic into different segments.
- People in McMansions who don’t understand extenders and use two different SSIDs for each half of their house or for indoor vs poolside.
- Phone is on cellular network, speaker is on WiFi, “controls don’t work”
- Network teams who won’t “open the ports” or configure mDNS or Zeroconf or Bonjour but will let port 443 to the internet.
- people who want to turn their speakers on at home while they are at work, for their dog.
- people who want to turn their speakers off at their second home after they returned from holiday and left the pool party music playing.
- diagnostic logs that would be nice if they went somewhere.
- People who lost their phone and want a website on their laptop to control their speakers.
- people who have their speakers nicked and want to login to your website to see their speakers checking in and “remote wipe” block them.
- People who want the status of all their speakers live in their phone app, even the ones at other properties.
- tons of buggy low quality, low cost, network devices (switches, hubs, cables, routers, firewalls, NATs).
Just about the only thing which is used enough to be reasonably trustable on any random customer network is HTTPS to the big CDNs and Cloud providers.