Complete novice at all of this if asked question would probably get brushed aside. I will ask just in case I could be wrong.
Wind power is good thing.
What is with this heated debate about different shape of sailboats?
Some are narow some are wide. Narow is slow, wide is fast. What is safe, what is not for ocean travel?
Not a question of being brushed aside but what you ask is what this thread is all about. Stick around and you learn. If you like boats and your desire to learn is strong enough go to the beginning of the thread and start reading it. Many has said that they have learned a lot. Certainly I have learned while doing it
Regarding your questions: Narrow is not slow and wide is not fast. There are narrow boats fast and narrow boats slow. The same with wide boats.
Some narrow boats are in absolute terms faster than beamier boats but to be faster they need a crew. If both boats are sailed solo then the beamier boat will be faster because it is easier to exploit.
Two different concepts, both modern, both with advantages and disadvantages (there are a lot of discussions about that on the thread).
Regarding safety for offshore sailing that is not also a question that can be defined between narrow and beamy boats. I would say however that in what regards modern light boars and smaller sizes, if less than 36ft, a well designed beamy boat can be more seaworthy than a much narrow boat of the same size simply because it is possible to have an overall bigger stability. But mind you that I am talking about possibilities, in reality each boat is a case and has to be looked and analyzed individually.