It's bad advice for any address, legacy, segwit, or otherwise. We have seen plenty of clipboard malware which will replace addresses with ones with matching characters at the start and at the end. It is trivial to create a database of millions of addresses for the clipboard malware to draw on and pick one which is as similar as possible to the address it is replacing to try to avoid detection of people who are careless and only check 3 or 4 characters.

The only safe method is to check the entire address, regarding of the address type. It takes less than 10 seconds to do. I have never understand why people would be so careless and risky losing their coins for the sake of literally a few seconds.