Once this exists, it will just be a matter of time until it becomes mandatory. This is a guaranteed fact.
The US Postal Service has existed for over 200 years, and at no point has it become mandatory. We could easily provide half a dozen other major government initiatives which intersect with commercial activity and do not seem remotely on track to mandatory usage. What makes this particular initiative different? If the postal service were created today, would you also suspect that it would become mandatory in a matter o…
Edit - And furthermore, it's a govt issued id to track all your online transactions. This is tax revenue waiting to happen.