New "Register Copy Handler" Checkbox Redundant?

Luckily the following bug has already been fixed as of v3.8.2 - I am mentioning it for reference: I was going to report the bug from v3.7.4 that would not copy the folder timestamps when cloning folders to the same root directory.

In the preferences a new checkbox "Register Copy Handler" has been added. When it is checked everything works as before the bug had creeped its way in, but when it is unchecked the native Windows copy handler is used, in other words, TeraCopy is turned off. So, my question is, what is the purpose for having both "Register Copy Handler" and "Use TeraCopy as default copy handler" preferences?