11.69.3 Can you answer these questions?

11.69.3.1 Is there a reason to choose multiple local `\newcommand`s over multiple local `\let`s to a global command?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=752418

For context, I want a/some function(s) to only be defined in certain environments. I found (after much failed bodging on my part) the delightful function \AddToHook so I can use 
\AddToHook{env/myenv/... 
[macros] [environments] [grouping] [hooks]
 

asked by grepgrok https://tex.stackexchange.com/landing/r/digest?cta=user&id=258167 Score of 2

11.69.3.2 RFC: An new (?) alignment environment

https://tex.stackexchange.com/landing/r/digest?cta=question&id=752394

One of the issues I have with ams alignment environments is that they use "cells" which change in size to fit their content. This is required for all cells which are used for alignment, but ... 
[math-mode] [expl3] [alignment] [code-review]
                                                                                  

                                                                                  
 

asked by Tohiko https://tex.stackexchange.com/landing/r/digest?cta=user&id=93163 Score of 2

11.69.3.3 Autonum with multiple long equations in one align

https://tex.stackexchange.com/landing/r/digest?cta=question&id=752419

Usually (without using autonum) the equation number is moved a little lower if an equation is long, so that the number does not overlap the equation. 
When using autonumhttps://ctan.org/pkg/autonum (I ... 
[equations] [numbering] [autonum]
 

asked by schnefl https://tex.stackexchange.com/landing/r/digest?cta=user&id=285358 Score of 1