Not a pure shell, but Makefiles do rely on whitespace.
I never understood why so many people care about that (not to mention that python uses the curly braces as a useful syntax element for dicts & sets)
I use Python a lot so it's not a deal breaker to me, but even after years of use significant whitespace is still firmly in the "bad ideas" category for me. It's form over function.
When I code in C and move some code around I can just tell my editor "reindent this code" and it looks fine immediately. With Python I always have to double-check to make sure everything is in the right place.
Similarly I almost never have to reindent anything manually in C. The editor always knows where I should be based on the number of open braces. In python I often have to readjust. A common situation where that's annoying is if I want to add code after and outside a block, in C I just tell vim to open a line after the closing bracket and I'm immediately at the right location, in Python doing this will have the cursor at the wrong level of indentation.
It's not the end of the world and it's bikeshed territory but for me significant whitespace is in the same category as automatic semicolon insertion in JavaScript, I sorta get why somebody thought it was a good idea at some point but it's just more trouble than it's worth in practice.
Python wanted to be the anti-perl and it went too far in some places. Pseudo-code is only "pseudo" for a reason.
I get the point about moving code around, I guess it can be problematic with some tools. In my experience PyCharm gets it right, and when moving around code in vim I can just change the indent level on the whole block at once, but it is dangerous to miss a line at the end and move it by mistake one level up.
Also I feel like changing the indent of the cursor (manually) when exiting a block is more or less the same work as typing }, and I got used to it to the point it becomes automatic.
But I guess at the end of the day it's a matter of priority. Is that more important than having special syntax for dicts? I really like the fact that we have the tuple/list/dict distinction, and would be great if we had a different paren type for sets (which would have eliminated the {} vs set() issue). On the other hand, going with begin..end or if..fi blocks would be even more antagonizing than using whitespace.
Makefiles don't gernally have anything more than one level of indentation that is significant.
People care about significant whitespace because it's inferring heavy semantic meaning from something that's by default invisible, and even when shown visibly, may not actually be particularly obvious.
When I code in C and move some code around I can just tell my editor "reindent this code" and it looks fine immediately. With Python I always have to double-check to make sure everything is in the right place.
Similarly I almost never have to reindent anything manually in C. The editor always knows where I should be based on the number of open braces. In python I often have to readjust. A common situation where that's annoying is if I want to add code after and outside a block, in C I just tell vim to open a line after the closing bracket and I'm immediately at the right location, in Python doing this will have the cursor at the wrong level of indentation.
It's not the end of the world and it's bikeshed territory but for me significant whitespace is in the same category as automatic semicolon insertion in JavaScript, I sorta get why somebody thought it was a good idea at some point but it's just more trouble than it's worth in practice.
Python wanted to be the anti-perl and it went too far in some places. Pseudo-code is only "pseudo" for a reason.