I can see three reasons:

1. They have left over capacity that will go unused otherwise. Most users have hit their limits before the end of the week. Might as well get some use out of the servers.

2. A backend change made migrating usage tracking hard, inaccurate, or impossible.

3. A usage tracking issue meant the usage wasn’t accurate anyway and they needed a reset to save face / avoid contract breach.

The addiction or marketing strategy seems too clever. Why explain something with cleverness that can be explained by laziness or stupidity.