It may annoy those who use multiple desktop/laptop/mobile devices or must re-register after a crash/change in choice of devices.
On the other hand, once the font is downloaded, it is the patron’s responsibility to perform due back-up/transfer chores.
Furthermore, the “My Account” interface allows unlimited re-downloads.
Therefore, also highly recommended!
The above options may be applied to individual fonts per partner preference. They represent the sole power of THP to limit illegal distribution of your work. There is no way to prevent deliberate upload/download of fonts after purchase.