Learning is generally thought of as an intellectual activity, but that’s only partially true.
Though learning something new always seems to involve mental effort, some things simply cannot be grasped intellectually. You have to do them to learn them, and ‘understanding’ might only come with experience, or not at all!
Take creativity for example. There are plenty of things you can do to increase your chances of creative productivity, but you can’t ‘learn’ it in the same way that you might study the rules of, say, algebra or musical composition. The same is true of parenting, baking, gardening, riding a bike and indeed most of the stuff we do.
This applies to many professions as well. You can study the theory until you are an expert, but won’t make you a consummate professional in your field. Competence and proficiency only come with practice, and that means doing rather than theorising.