This topic has been covered a few times in the past and it all boils down to if it makes you sleep better, then get a warranty.
Financially it just doesn't make sense on a well maintained and known car. If you look at it on average the policy cost is the claims paid, plus administration costs, it, taxation and commission to sellers etc. and a nice profit. Of course there's always someone who got a new gearbox or engine, so they are the winners, but the majority lose vs successful claims made.
Basic maths running 2 cars at say just £500-£1,000 per policy per annum over 10 years would cost me £5k-£10k. In the last decade I've had one big bill of £4.5k for a failed turbo on an Evoque and nothing else that's not been covered by Consumer Credit law, or the remains of factory warranties. Most policies would have a limit anyway, as some have mentioned, so I'd have been capped.
My virtual fund therefore is at least £5k in credit over just the decade and I sleep well at night.
Reality is I've avoided such policies alongside, GAP insurance, tyre and wheel protection, protected NCB, (and PCP, loan interest) etc. etc. etc. for many decades and bank roll myself.