I like how they (just like imessage) allow you to message someone who cant possibly read the message because they have no whatsapp. Then again, I think they can

I like how they (just like imessage) allow you to message someone who cant possibly read the message because they have no whatsapp. Then again, I think they cant even deliver the message over sms on iphone? SMS is only available in the apple app if you first force it to send SMS?