I will not get into arguments with someone who is obviously against tyre sealants, I will simply refer you to some test reports from the the experts in this field. No doubt you will question even the experts findings.
http://www.ultraseal.biz/pages/testreports.htm#RAPRA
For your information Ultra seal is used in racing, both cars and motorcycles, both on road and off road
http://www.ultraseal.biz/pages/about.htm#eurochamp
but then you will say he is not a real racing driver!
I can give a lot more examples but I feel I would be wasting my time. I did not set off this thread to defend or sell this product but as my way of getting round the lack of a spare wheel. In fact even if I did have a spare - as I do on my other vehicles - I would still have my tyres treated. I would not want my wife or me to have to change a wheel on the side of a motorway on a dark wet night and this is what Ultra seal is for. You have he option to replace the tyre when it has got you home safely or continue to use it for the life of the tyre.