lambda v list comp

[snippsat]

I hear lambda is significantly faster than list comp? So it is easier on resources.

Not True in most cases are list comp faster.

λ python -m timeit "list(map(lambda x: x+10, [1,2,3]))"
1000000 loops, best of 3: 1.2 usec per loop

λ python -m timeit "[x+10 for x in [1,2,3]]"
1000000 loops, best of 3: 0.463 usec per loop 

Functional style can have advantages if done right,not talking about speed but less side effect.
Can go down a rabbit hole if talk to people who love functional programming
Python is of course not a functional language,but has support for a functional programming style.
List comp is looked upon as more Pythonic.

Why would you press space 4x?

No one press 4-space,Tab is set to move 4-space in almost all Python editors.
If not configure Tab to move 4-space.