It was most likely that Vanilla Ice was loyal enough for DIO to not care about Cream, or that Cream took too long to catch him off guard. Whitesnake is much more physically faster, and with an arguably stronger and more useful ability than Cream.

But a stand that can literally disintegrate a person into a void instantly and become invincible just feels more terrifying/powerful than a stand that requires physical contact to take stands/memories etc in my opinion.....