How exactly is it a bad idea? I don't get it. Perhaps it's because I'm a
newbie or stupid or both.

Since you seem to know so much about what are and aren't good ideas, could you
please explain me why is it a good idea to have walking commands (which stop
when the terrain changes) in the first place? Those commands make the game...
oooh, scaaary... easier to play! Ooh, we are spoiling the poor newbies with
such easy-to-use commands. They might learn some bad habits! Let's remove
these aiding commands right away!

Could you please explain to me why it is a good idea to stop walking when the
terrain changes but it's not a good idea to stop walking when you could die by
moving further? What's the point in the walking commands in the first place?
Why do they exist when you could simply type "20 s" for the same effect but
with increased risk (which seems to be a "good idea" according to you)?

It's a good idea to stop walking when terrain changes because I'm used to stop
walking when the terrain changes.
It's a stupid idea to stop walking when I take damage because sometimes I want
to drown myself in the moth outside BC.