Using JUST the rear brake for a CONTROLLED stop is OK, if it works for you.

Using JUST the front brake for a CONTROLLED stop is OK, if it works for you.

Using JUST the rear brake for a PANIC STOP will likely not end well, i.e., across the hood of a car. (Happened to me.....)

Using JUST the front brake for a PANIC STOP will likely not end well, i.e., "dead sailor". (Happened to me.......)

Using BOTH brakes for ANY stop will almost always result in a superior stopping experience.

It's your bike and your ride; you make the call. But if you crash into me, the failed stop will be the least of your problems.