Yes helpers lines rocks but it's more for "construction" of the object
or verify one object

I see more something like that :)

Say you have some separated volumes (100) on a ground flat plan
in a 3D view you can see in a flash those who are not parallal between us or not perpendicular to the plan with the system of colored edges axes ;)

Or in a front view those who seems vertical at the eyes but who are not because there is 0.5 ° deviation
etc...

if it's not a "flat ground" I use the Custom Plan ;)
(in this case colored 3 axes must follow for adapt to the volumes who are not changed! )

Of course colored system must be disable / enable at any moment ;)
It's a cool tool of speedy verification