When Voodoo 2 was released 2 of them died from overheating in my P200 MMX. They always needed active cooling or a case with major airflow. Ultimately i put active cooling on my Voodoo 2 board after the 2nd one died, 3dfx was willing to keep sending me replacements but I didn't want the hassle.
You are joking, right? There were probably more than one million people using Voodoo2 cards without any cooling, and without problems. Especially on P200MMX you should have no problem at all, a V2 on a P200MMX should be barely warm, unless you have some other problems in the system (like a bad power supply or motherboard).
Even on a PII system it's ok to run V2 without any cooling at all, I had a friend back in the days that had PII 333 overclocked at 500 MHz and with two V2s in SLI without cooling, he had no problems.
Of course that some cooling will help, but it's far from mandatory.
However, from my experience, cooling is needed as you start to approach 1 GHz CPU, especially on Athlon systems.