Some beers, like my oatmeal stout, are great with just a bittering addition. The bittering charge balances the sweetness of the malt, but doesn't leave hoppy flavor or aroma.
Some beers, like IPAs, have moderate to high bittering, but lots of flavor and aroma hops too because that is what the style demands.
Other beers are in the middle- some German lagers have just bittering and flavor hops.
Of course, anybody can make a beer the way that want- that's the great part of brewing. But a hoppy oatmeal stout would be very weird to me, while a non-hoppy APA wouldn't be to my liking either. While I"m not always adhering to the BJCP guidelines, I really like knowing what to expect when I order a beer. I'd be very disappointed in a brewpub to order a hefeweizen, and found out when drinking it that it was loaded with American flavor and aroma hops!