I’ve never felt the need for a parking brake on a GA airplane.. I can either taxi the tailwheel into the grass or gravel, or park perpendicular to any slope.. then jump out and chock it. To leave without the plane rolling away, I place a pebble or stick behind the tire, remove my chock and jump in. My reluctance to have a parking brake is because one day, my buddy was test flying a new build, the owners installed a valve, but didn’t hook up the cable to the handle. The handle shook into the closed position and after landing, he applied brakes and the brakes applied but wouldn’t release. Had he “tested” the brakes on short final (or applied then after liftoff to stop wheel shake), it’s possible he would have flat spotted both tires or even nosed it over!