No, I will not lose my work. After each shoot, I run two backups: one to the online backup disk and one to the portable, both before i format or re-use the memory cards. That takes me less than a minute to initialize.
Probably nothing wrong with RAID, but after having worked with computers since the early seventies, 20 of those years as my main profession, I have learned to appreciate simple standards, where I have control, not the computer. If 5 billion people mean otherwise, I don't care. My system works for me.