They DRY FASTER!
There. That's it. Well, almost. The colors are luscious, and the formula contains a little beeswax, which makes the soft and very creamy consistency hold up to thickly applied impasto techniques with no falling or globbing. (I think "globbing" is a technical term, yes?)
I ordered and tried the Lukas Titanium White first, just as a test. It skinned over in a day (a DAY!), and was nearly completely dry in about 3 days.
Since then I've added more colors to my arsenal, and find the earth colors are true, while the newer mixes of synthetic components require a bit of a learning curve. (Example: Lukas' Green Earth is really quite blue.)
Drying time is such a big factor in my work schedule. I ship or deliver regularly to the places that show my paintings, and getting work out on time means a lot to me and my venue owners. Every trick like this helps!
Want to find and try Lukas paints, too? Do a simple Google search and begin your newest oil painting experiment.