I had the extended warranty on my last bike, a K1600GT, because I was terrified of something really expensive going wrong. Nothing did.
Also had it on my current TC but recently decided to cancel it. Again, have never used it.
As Micky says, it's a gamble, but the bike that you have is probably the most reliable of the line. Plenty of used spares available, too. Need an ECU? £70-£100 on eBay and works as well as the new one at £600.
Plus, it's not the same as the original warranty. Engine casings corroding aren't covered, for example. Usually a £100 excess or pay a higher premium.
The thing that made me decide to cancel was the fact that it had to be serviced by a BMW dealer to maintain the warranty and I couldn't take it to the experienced independent that I found and trust. Something else to factor in to the difference in costs, particularly if you are doing more miles this year. Even with modest mileage, with the difference in servicing costs plus warranty premium, reckon on a difference of £5-600 in a year.
The breakdown recovery anywhere in Europe is a nice idea but, really, how likely is this on your bike? Has it ever died on you up until now?
I've found a motorcycle breakdown recovery service that covers Europe for £68 for the year.
Find a good, recommended, independent mechanic to service it at the correct intervals and I don't think that you'll go to far wrong. Mine is a 2010 TC and I've just turned 26k miles, 14k in the last 12 months with nil problems and there's plenty on the forum with more miles on earlier models will few problems.
In the end it's your choice, but they're not getting any more of my money and it's not causing any loss of sleep.