Occasionally isn't good. It either has to work consistently or not at all. If someone has wrong understanding what the time is and their clock goes to "wrong" time occasionally it is bad.

And on other hand if marketed people expect such features to work. Even indoors or in basement. Next to window facing right direction in lucky meteorological conditions is tough ask for majority. Geeks will geek out when it works once in a bluemoon. But regular people expect it to work every day or even every week.