How can anyone say accents are important!
Take England for example, there's a basic english one which most foreigners will hear as similar. Then there's the main north and south differences. Then within the South there's a general one, a posh one, cockney, bristol and west country.
Then in the north there's lancashire, yorkshire, tyne etc. Then within these there are even more! Like Scouse, Mancunian, Geordie. Then within places like Greater Manchester you can tell differences between Salford, bolton and Oldham etc.
I think pronunciation is important, but I think learning an accent is a slight waste of time. Many English accents arn't understood in America, new zealand accents in Australia etc etc. From my own experience, It would be best to learn the accent for where ever you live. Because not only is the accent different but many words will be too, for instance.....
thongs, jandels and flipflops are all the same item, just different words used to name it in different countries. If an Australian went to England and said they are wearing thongs, a pair of rubber sandles wouldn't spring to mind.......