Egg whites are a good source of high quality protein, & protein certainly isn't a bad thing. What's worth pondering is whether supplementing high methionine protein into a diet already replete with protein from other sources might be unwise. The "more isn't always better" argument. If your diet is mostly fruit & veg, a little supplemental egg protein might be beneficial, but if your diet already contains red meat, chicken or fish etc, my humble opinion would be against supplementing additional egg protein.
Nothing wrong with dietary eggs in my book. The yolks were demonized because they contain cholesterol, yet most are now in agreement dietary cholesterol doesn't effect blood cholesterol levels significantly, so this was most likely a bad call. Nothing wrong with the whites either, which are a great source of protein, but again; if you're diet is already replete with protein from other sources, I wouldn't throw more protein into the mix with protein supplements; particularly high methionine egg white protein supplements.