Whether the added expense of no claims discount protection makes sense for you depends on your driving history, the size of your discount, and your insurer’s policies.
Typically, the added expense of no claims discount protection doesn’t make sense for drivers who only have a year or two of no-claims discount. In many cases, insurers won’t even allow you to purchase the protection unless you have three or more years built up.
But if you have a hefty no claims bonus - the 60%+ discount on your premium that five or more years of clean driving can buy you - the protection can be a sensible precaution.
But you should also consider your insurer’s policies. Do they completely wipe a no claims bonus for an at-fault claim or do they just reduce it by a year or two? Do collisions with an uninsured driver or in a hit and run - often technically classed as at-fault claims because the insurer can’t recover the costs of the repair - reduce your no claims discount? How many claims are permitted under the protection?
The more likely your car insurance provider is to completely reset your no-claims bonus, including for collisions that aren’t actually your fault, the more sense the protection insurance means.