Yes, you could. What about the person Mozilla claims to want to get into coding? They have to choose between getting the regular updates vs being able to tweak their addons.
And do you plan to set that all up in the middle of your workday when a forced update disables your extensions?
Again, you can also use the developer edition, which also allows unsigned addons and has automatic updates but also doesn't disable your extension. It's specifically meant for people getting into coding.
Plus, there is more ways than developing FF addons to get into coding that Mozilla wants to stimulate, developing the browser itself or websites is also an alternate goal you can join in addition to trying out making your own addons.
And do you plan to set that all up in the middle of your workday when a forced update disables your extensions?