To crimp, or not to crimp, that is the question.

I just started loading my own 223 tonight and it is intended for use with my semi-auto AR rifles. I have 100 rounds ready to go. I have not crimped any of them.

Is crimping my 223 really necessary?

I've been loading 224 Valkyrie and 308 for a few months now and have sent hundreds of these rounds down range successfully without any crimping. If it works for the 224 Valkyrie and 308 in semi-auto rifles, why wouldn't I achieve the same results with my non crimped 223?

What philosophy do you subscribe to and why?