Sorry, been away for a day or two.
The steeper angle frames are often shorter in the top tube, so you can get a good position on tri bars.
Some road geometry bikes are too long so make setting up tri bars a pain.
I train on a road geometry bike, but race a steep angled one, and can ride the race bike much quicker.
But it is lighter, has better wheels and different gearing.
As for my next bike - It will be either carbon or titanium, probably steep angled, as I like the riding position.
At the end of the day, I've got to be comfortable on the bike for around 6 hours, then get off and be able to run a Marathon, and I favour a steeper angle frame for this.
Paul.