Today if you are using any Microsoft technology - browser, websites, Sharepoint applications, UWP apps or UI; one thing is common and that is that they scale and adapt to displays of different form factor. This may be taken for granted today but this would have been impossible without the APIs many of which were made only because of Windows phones & W10M and the idea of making a UWP.
Microsoft may term W10M as a failure and as something that should have been avoided, but I feel that the journey from Windows 7 to W10 and finally to WCOS was impossible without Windows phones.
What do you think?