It creates a better neg connection path to the driver (cannot be accidentally interrupted by unthreading), so it is actually advantageous for most end users who aren't as technically inclined.
On their other lights with the tail button, it lets them use the housing as the signal path instead of having to use a double tube (Acebeam/FW3A/KR1) or signal wire (HDS).
For a company that sells millions of dollars in lights a year... they actually do not seem to care about the bottom line on their batteries. From personal experience and others' reported ones, they seem to give them away just as frequently when a customer experiences an issue.