In all fields of knowledge (in math this is very important) complex knowledge is built upon simpler knowledge. Also, the building does not have to be strictly hierarchical - often concepts are borrowed back and forth in different areas.
For example, if writing computer programs, having a good feel for how much work is involved in doing certain types of math problems is key to writing computationally efficient programs.
The good mathmetician draws upon all their learning - including the fundamentals - throughout their career.
Also, oftentimes ideas from disparate fields of study can be related or of use together; ideas can be “borrowed” from what would seem like a completely unrelated field.
Education therefore should be “broad” as well as deep. This goes into the making of the so-called “renaissance man”.
Many people doing very advanced work make gross errors in their thinking that reflects the fact that they do not have the fundamentals of the relevant fields drummed into their head.
It is important for people in all walks of life to have an excellent command of the fundamentals of a broad education; they should not be neglected by skimming over them then using a “black box” to provide a glossed over “solver” too soon in one’s education. Only after the student has exhibited a very solid knowledge of the fundamentals should machinery be introduced.
Most general students have no need of computers for k-12 education other than as a typewriter. Other than that, they are simply a plaything.
The only students who really need a computer are those in programming classes.
Using a computer actually misallocates curriculum time away from reading classics, etc. and uses it instead for silliness. How else is that that educations 100 years ago were generally far superior to those today for those who go through the whole system and graduate college.
You don’t have to go back 100 years; 50 will do nicely to illustrate the disaster.