Textbook authors be like:

sintx^2 + cosπx^3 - 3

I find it far more efficient to parse. I also put superfluous parenthesis in my code where I feel it helps readability.

It's something to judge on a per-case basis, it'd also work very well to use whitespace (i.e. 25 - 5/5 instead of 25 - 5 / 5). Of course you don't want to parenthesis everything but it can help a lot.

Simple rules are only simple if they are intuitive and consistently applicable. Otherwise, they are nothing more than yet another thing to remember and think about, yet another source of error, and yet another possible point of confusion. With enough time/ effort, one can brute force the intuitiveness, but that doesn't automatically make the rule good or universally useful.

As a math teacher, I can assure you that not everyone has the same level of understanding or knowledge when it comes to order of operations. Some people struggle to remember the specific order, and mnemonics are worthless. Others struggle to read or visually process problems written with unclear or inconsistent symbology. Hell, most people don't even learn exactly the same fucking rules. Tell me, where is the simplicity in all of that?

When I teach order of operations, the glass eyes and exasperated sighs of frustration come out. But when I teach just the parenthesis and exponent stuff, lightbulbs and understanding. Suddenly, people "too dumb" to do 2+2 are doing algebra and getting excited about math for the first time ever. Some of this is certainly a failing of our collective education system, but we can't just forget that everyone has their own flavor of learning disability, neuro-diversity, and life experience. Simple rules quickly fail to be simple in the face of complex people.