No.
Unless you want to do research, you should not do an MD/PhD. Having a PhD does not really make you a more attractive employee for most private practice opportunities - unless there are areas you studied during your PhD that are applicable to an area they are emphasizing.
Doing a PhD requires an extra 3 years (at least) of training - and while people who start med school with you have finished their residency, fellowship, and are making good money, you are still in residency.
Most MD/PhD people go towards an academic career, which is lower pay but a different set of rewards, and a different lifestyle.
I caution you - clearly, when you read boards like this it seems like MD/PhD candidates do better in getting lots of residency interview offers, etc. And perhaps they do, but not always. They often tend to be competitive candidates. But doing an MD/PhD for the purpose of improving your competitive advantage is highly discouraged. I can't really think of anyone who would recommend this.
It is worth it if you want it to be worth it, and the PhD study impacts the area in which you are planning to work for your career. If you want to get a PhD, and then go into private practice and have nothing left to do with research, what's the point? So you got an interview at a place you might not have gotten an interview at. But a lot of the competitive programs make it a point of trying to train physician scientists, and while not fully discouraging residents from going into private practice, do actively encourage academic careers.
PhD is a huge time commitment - many people go into it and then drop out when they realize this, or when they realize it isn't interesting them as much as they thought.
It may be an advantage when looking for an academic job, yes.