>>118783751) Online gaming - a first to be available in consoles by default.
2) Clean and crisp 3d - just like many consider SNES graphics better than NES graphics for 2d, 6th gen gave 3D the nice detail and framerate that it deserves. Also like how you don't need anything more than SNES for good 2D you don't need anything more than 6th gen for good 3D.
3) Sega's first party games: Sonic Adventure, Sega Sports, Ecco, Jet Set Radio, Shenmue, Phantasy Star Online, Crazy Taxi, Super Monkey Ball and many more - these were strong game series and several of them continue to this day.
While I agree they weren't in a good position to decide to lead the next gen, the saturn was the first fourth gen, so it was their "turn" again to come out with a console by that point. Also, the dreamcast was powerful for its cost of only $200, while the PS2 came later and was $300 while not being too much superior.
4) I suspect the dreamcast was also very easy to work for, that's why there are heaps of conversions of fifth gen (including PC games) to dreamcast.
We can look back and say it was a mistake because it didn't work, but it might have been worse if they had waited.