I have one on my
280, and it does not have Kessy, can't have too much security I think. I also have CCTV, outside Security spotlight, secure house doors, windows, with alarm system too.
I have put the DiskLok key on both of our house keys keyring - just in case one of us forgets/misplaces our house keys after fitting the DiskLok that I tend to always leave locked and so ready to fit without keys (maybe a bit silly, but each to their own).
My main plan with DiskLok is that if anyone has a good look at my car, and sees DiskLok, then hopefully they will move onto the next car - selfish but that is all we can do, I've also got the OBD2 port covered with a machined block as my car is an Audi S4 and for some reason people are still trying to take them away! Note the OBD2 port in my car is very close to the driver's side of the car and it has been said/proved, that you can just reach it without activation the interior monitoring system!
One other thing, in general with VW Group cars and probably others, there is a deliberate delay in the alarm system, so that even if you buy a kit of these lock openers which allow you to unlock the car without damaging the lock barrel, when you open the driver's door, there will be a 15 second (I think) delay before the alarm starts to sound, that is plenty time it seems to stuff a bit of kit into the OBD2 port and generate a synthetic key which will disable the alarm, unlock the electric steering lock and allow you to start the car! I might be wrong about the length of the alarm delay, it will be there in case the remote central locking fails and you need to use a key to open the door - and then the plan is to quickly fit your key into the ignition switch - or suffer the alarm sounding. Many people have altered that delay using VCDS etc.
Edit:- if considering buying DiskLok, remember that it is a nuisance to fit and remove, but then you will be putting added security before convenience, also consider buying the horrible yellow version as it is a lot more visible to nasty people than the more classy looking silver painted version, I did not have a choice when I bought mine and so have the tame silver painted version!