The old saying applies here: "If it doesn't kill you, it will make you a better person," or something like that.
One could argue that I learned some basic sales and public speaking skills being a Wt slave. But I would counter that there are easier ways to learn these skills.
I also disagree with the statement that the Wt teaches you how to study. Underlining a Watchtower is not studying; nor is relying on unsubstantiated quotations from non-cited works (as is common practice in wt publication).
I completed a doctorate degree several years ago. The hardest part of my education was unlearning many of the study habits I acquired while in the watchtower.