Old Interix required retargeting and recompiling binaries, similar to how you would need to recompile to target the differences between Linux and BSD. WSL runs Linux binaries without the need to retarget or recompile specifically for Windows.
This also means that the long tail ecosystem of Ubuntu PPAs and custom binary download sites all mostly work, too.
Ah okay. Shame that calling this "GNU/NT 10.0" would not be proper then.
The Subsystem for Linux is essentially an implementation of the Linux ABI, which is distinct from UNIX and provides true binary compatibility.
The ironic thing is that WSL itself is deliberately not Linux; the only similarity is the user-space ABI.
Unfortunately, I've met very few developers (admittedly interacting mostly with students) who have any understanding of what is Linux vs. GNU utilities vs. UNIX, vs. Ubuntu. "macOS is basically Linux right? Its because of the Terminal". screams
You'd be amazed how complex and difficult product naming can be ;)
Just be glad we didn't call it WSRPGLCB - Windows Subsystem for Running POSIX, GNU and Linux Compatible Binaries ;)