I took a course from Leslie Saeta!
I don't use a palette knife very much but it's always useful to have another string to your bow.
The best thing is, like everything just to have a go and practice. Leslie uses smooth gessobord rather than canvas as she says it is easier to move the paint around. She doesn't use many knives, just a small, medium and large.
She does online classes if you cant get to one of her workshops.