Olive oil can go ransid, so not good for food items or
mods. I'm not actually sure what salad bowls and the such have on them.
I do put finish on as much as possible, inside too, but in some cases there is already a brass tube in the atty hole, so I've missed that area a few times. When the oil is applied and looks wet, the grain does pop, slightly duller when dry, but improves again after sanding and again after waxing and buffing. Poly is probably shinier, but is a different beast.
There is some darkening, but most noticeable with a lighter wood. Darker browns and reds don't show much change, especially as the grain is brought out. Ash and curly maple show more. Here is a pic of two mods from the same stock, on the left it is about 2 or 3 years old (been
vaping this morning, so excuse the crust on the mouthpiece) and on the right it is just about ready to have the wood finished but bare for now.
You dint say, but what wood are you working with?