The idea
Pure man pressing follows your player everywhere — great for access, but you can be pulled out of shape and beaten by movement. Pure zonal pressing holds space — great for structure, but it can let a free man receive. Hybrid pressing mixes them: man-oriented in some areas or against some players, zonal in others, switching based on cues. Mackenzie's pieces trace why it's become the default; the follow-up on the 'evolutions' of the hybrid press is worth reading too.
What it teaches players
This is where I'd push a player's understanding, because hybrid pressing can't be a rule — it has to be a read. 'Mark your man here, but if he drops and you'd leave a hole, pass him on and hold the space.' That's a decision, and it demands that players understand the purpose of the press, not just their instruction. I think players can handle far more of this than we give them credit for. Given the why, a fifteen-year-old can absolutely learn to switch between tracking a man and protecting a zone. That's real football intelligence, and it's the kind of thing I want us developing.