Artists

Light can pass through the color from the underpainting or ground resulting in a luminous effect that's difficult to replicate with acrylics even with similar glazing techniques. But an underpainting in acrylic that's then painted with oils can produce remarkable results in less time.
(just don't put acrylics on top of oils!)
Also consider Japan Dryer for speeding up oils drying time.
There are "water based" oils that can give oil-like effects with easier cleanup but I find the colors a bit subdued.

Then there's the fact that acrylics have only been around for a few decades, and their longevity is still unknown by comparison.

Most colors in both mediums are designed for long shelf life and most real snobs will grind their own pigments and control the color saturation themselves.