Persons on dialysis have a hard enough life as it is, treatment is expensive as it is, but luckily Medicaid covers it (As Renal Failure is a disability). Travel is next to impossible outside of the country, as necessary treatment is well outside the economic realm of most patients. Even if one could afford to travel, the price would be doubled if only for the treatments alone.
The NHS WILL cover emergency treatment, but if a patient is in need of that, then their overall health can drop quickly. By covering this procedure overseas, it would improve quality of life for an already suffering segment of the population