2nd point. Students should seek lessons by progression. Good instructors can be found at any level. If you are 2200 - then a IM or GM would be excellent. If you're 700 a 1700 can make for a great coach - if experienced. I'll guarantee I'm more successful at teaching new players than a GM as Naka could ever be. For one GM's have little or no experience in teaching new players. Their chess knowledge doesn't translate to the beginner. They'll shout the usual tactics/puzzles and disappear. Why? It's the same in every sport. The elite are Doers, seldom have the skills for teaching new players. Just look at sports teams and who are the head coaches? Usually ex-players of ordinary skill performance, but able to communicate and recognize the essential.
I suspect not a single player that's posted here "study tactics" has an ounce of hands on experience of teaching more than a few. They're just repeating the advertisements - believing "Naka improves his chess by playing puzzle rush". Perhaps he does - but so what. Notice he's not playing it anymore and his OTB rating has taken a dive?
The truth is for a 700 rated, puzzles should not be a priority. Truth is, there are better ways to practice tactics than doing a few mover puzzles. Truth is until 5 years ago coaches instructing new players did NOT emphasize tactics. This is a recent phenomenon on display here by lazy instructors giving students standard puzzles to study - as if were a homework assignment.
Serious tactic study will prove beneficial, but only for players who are at that stage of development. My point is there exist far better ways of investing study time for players <1000.