I do believe it is essential for some loads/calibers/guns. But not for all. That said, I don't, and won't reload without one.
I have owned about a dozen over the years. The two I have still are the cheap Caldwell and the MagnetoSpeed. I still use both, but the MagnetoSpeed is the best for rifles, and what I use most.
Yes, I had a Labradar, after the last fix, sold it. Too fragile, too many faults as compared to the MS. I have friends who love theirs though.