I believe this was a topic of discussion in the Straits Times in the recent past, no?
To me, it's all about practicality. I was in Australia for 5 years in the early 90s. My first year, people were having a hard time understanding my English. Most of the time, they stared at me blank (gave me that "huh?" look). I had to make sure my "th" sounds like "th" and the "r"s are pronounced. My friend tried to correct the way I say "tree o'clock" for a long time. After a while, I had to develop an Aussie accent to increase understanding.
Today, I switch between accents naturally depending on who I'm talking to. Where I work now, there are only 0.5% Singaporeans (there are Americans, Aussies, Dutch, Germans, Kiwis, Koreans, Canadians etc). I don't even think when my accent changes in between conversations. This works not just for English but for Chinese. Because I work with many China chinese in a particular Province (and particular prefecture), my Chinese started switching after about 5-6 years. If I switch to the local accent, you won't be able to undertand what I say
. But among Singaporeans, Singlish automatically comes in.
So I would say, language is functional. The point is to communicate and converse. If it serves it's purpose, then no problem. However, using an accent for the sake of using it (eg a Singaporean speaking to another Singaporean in a foreign accent) just doesn't quite make sense...