Sometimes we just do what is helpful and/or cost effective. Maybe not the optimum solution or technique, but helpful.

Is a vac-u-pan system helpful in relieving pressure in the crankcase and maybe even pulling a negative pressure? Yes. Is it better than a simple pair of breathers in the valve covers? Yes. Is it the best solution? No. Is it a fix for leaking rings? No. Is it much cheaper and easier than a vacuum pump system? Yes. Does it have any negative side effects if properly installed and maintained? No. Easy decision.