It's quite an in interesting title that NNGroup decided to pick for this.
Placeholders by themselves are never the issue
If you scan the internet, most studies talk about the following things that make
Using them as replacements for labels
This phenomenon became a common occurrence in the early days of minimalist approach in mobile design. Hence, people had to be told explicitly to not use placeholders.
Also, placeholders disappear when the user starts to type so it is an incredibly unreliable way of guiding the user.
Placeholders that are actually text that needs to be deleted are a big no-no.
If the placeholder text is too light or is too small, it basically infuriates the user rather than aiding them.
Browsers do not translate some attributes and placeholder is one of them
- Screen readers also might skip them
So, as long as they are used properly, they aren't harmful.
UXblog's article on Medium
UX Collective's article on some bad practices & some alternatives
Smashing Magazine's article on the attribute's accessibility issues