Only for personal usage, businesses may still need to show licenses and with telemetry, it’s easier for Microsoft to find such usages. That said, with the switch to Linux servers, Windows is probably a declining business for Microsoft while Azure and Office are growing, hence “Microsoft 365” subscriptions.
I believe for non-production usage, Microsoft is okay with unlicensed or trial Virtual Machines and such. The idea being that if developers are testing their software in Windows, that’s better than the alternative (not testing their software in Windows).
Similarly, if willing to beta test versions of software, you can get Visual Studio for “Insiders” and test the Enterprise edition for free with a non-production license for as long as newer beta versions are made available. (Note: IANAL, this ain’t legal advice, read the terms and conditions on any Microsoft VMs or software installations)
There is a permanent Windows Activation message (white text on transparent background) in the lower right part of the screen which my brain already blocked so it's not distracting at all. I only notice it after taking screenshots.
