At day one you don't know what you don't know, and uninformed self-study can get you off track. At this point you need to be led and hand fed: Listen, watch, imitate, repeat. One of life's paradoxes is that the more you know, you discover more things you don't know. You get the skill to identify the important things yet unknown to you, a major step in learning. As a beginner I think one should stick with doing what you know and concentrate on getting it down with the instructor. No need to dive in alone when you don't know the depth.
Suppose you want to learn orienteering, how to navigate in the wilderness. You could just head on out and hope for the best. If you survive the first week, you may have learned something by self-study. But wouldn't it be better if you had a teacher to let you know what plants will kill you when eaten, how to do basic celestial navigation, or use a compass or map a little? Knowing these things before going out on your own would certainly make your solo journey more productive and allow you to learn a lot more than if you headed out on day one relying on haphazard self-study.
The more you know to start with, the more you are prepared to learn and explore. You know what kind of things are important and what things are not so you don't waste time and effort. Having a teacher gives you increasing returns on your investment in self-study. You are guided in your search for knowledge, keeping your study efficient and on track.
So, with a teacher, IMO, no self-study on day one (practice, YES), a bit once you get the basics down, a little more at the intermediate stage, get involved after black belt, and immerse yourself in self-study as you progress higher in degrees. Over the years you gradually decrease your reliance on your teacher and assume more responsibility for your quest. If you're not motivated to self-study, none of this matters. If you are motivated, do it with patience and guidance for best results. At least, this has been my experience.