Not in the long run… Mayo Clinic only recommends the treatment for short-term relief. They refer to the low back and separation of the discs as its desired function, but effectiveness is questionable. In addition, not everyone can tolerate a significant amount of time in that position. Due to increases in blood pressure, more than one or two minutes is not recommended for patients with high blood pressure or glaucoma.
If you personally have found it to provide relief for short periods and have an extra $200-$400 readily available, then by all means go ahead and buy one.
For their price and limited effectiveness, I do not recommend them to patients. A better and cheaper option is to provide the neck with traction via a family member or friend gently pulling up on the head. I have a video of this on the headache doctor page.
Bottom line is that if you are to use an inversion table for pain relief, it needs to be coupled with a more comprehensive approach in order to find lasting results.