There is absolutely a point to having "conservative Democrats", just as there is to moderate Republicans. The only way to effectively run a political system that is set up like that of the USA is to have compromise--compromise that can be found when there is a degree of overlap between the parties.
Additionally, there aren't many truly conservative Republicans these days, judging by the pummeling that GW Bush has given the nation's finances--with the aid of the GOP in Congress. I often think that the single best thing for the US would be to have a few REAL conservatives in power...like John McCain, who will probably be the next president.
The tradition of intellectual conservatism in the US--ie, before it was hijacked by Goldwater, Reagan, and the religious fanatics who currently run the show is pretty compelling. It's hard to read William F. Buckley, for instance, and not think to oneself that even though you may disagree with some of his conclusions, you are dealing with someone very, very smart, who has given their convictions a lot of careful thought. That is not true of the current crop at all, and I think that's why we are beginning to see a schism between the intellectual conservatives and the wingnuts in Congress and the White House.