well..you can t say that the uvular thrilled 'r' belongs to standard correct speech..indeed it is a characterisation of south/southwest dialect in germany and it seems and as far as i know and remember it is an influence that came to germany from the french. this uvular thrilled 'r' is a characteristic of the french in paris. if you want to speek german correctly you should not try to use the uvular trilled 'r'. if you do it that won't be a problem but if you are not a native speaker of german that would sound like overdoing it. you should rather use the alvealor 'r' in german. this 'r' is also used in southern france. hope i could help you a bit! greetings, patty