No. I don't think taking a PHD will be a waste of time. However, I do believe that PHD is not for everyone, as taking this academic route entails a lot of compromise and sacrifice. First and foremost, you will be foregoing the opportunity to work fulltime in a company and instead devote at least 5 years of your life studying. This may sometimes prove to be critical especially in some workplaces that puts high regard in terms of tenure and experience. More importantly, instead of finally be earning and being able to support yourself after finishing an undergraduate and a Master's degree, you will have to live on stipend.
However, these sacrifices would prove to be all worth it in the long run. Starting a doctorate degree will give you access to research programs that are geared towards your interest. Doing research will not only satisfy your desire for knowledge but more importantly, you will be able to contribute to areas that are in dire need of solutions and further understanding. Other than this noble deed, PHDs do get higher salaries, and are seen as more competitive, especially in complicated and tedious fields of work.
I do think that completing a doctoral degree is still the pinnacle of educational attainment, and that nothing will ever compare to the fulfillment of having one. But if you are having doubts on taking a PHD, I would suggest that you think it over and over. Assess whether you are indeed ready because like I said, this choice entails a lot of sacrifice.