This sounds kind of logical, but really isn't.
In reality you can ASSIGN a task to a junior dev and expect them to eventually complete it, and learn from the experience as well. Sure there'll likely be some interaction between the junior dev and mentor, and this is part of the learning process - something DESIREABLE since it leads to the developer getting better.
In contrast, you really cant "assign" something to an LLM. You can of course try to, and give it some "vibe coding" assignment like "build me a backend component to read the data from the database", but the LLM/agent isn't an autonomous entity that can take ownership of the assignment and be expected to do whatever it takes (e.g. coming back to you and asking for help) to get it done. With todays "AI" technology it's the AI that needs all the handholding, and the person using the AI is the one who has effectively taken the assignment, not the LLM.
Also, given the inability of LLMs to learn on the job, using an LLM as a tool to help get things done is going to be a groundhog day experience of having to micro-manage the process in the same way over and over again each time you use it... time that would have been better invested in helping a junior dev get up to speed and in the future be an independent developer that tasks can indeed be assigned to.
These days when every iota of attention can be leveraged to the extreme by AI you can’t afford to tie up that attention testing a phone number input across 100 countries and interpreting the results.