LOLBRAID and Prashanth Kumar,
Be aware that others important reasons are related to the alt attribute : for SEO and for impaired people with sight disability using screen reader.
Some of the post from the answers here talk about it but few.
Edit:
For more details you can give a search about WAI-ARIA accessibility and SEO.
https://moz.com/learn/seo/alt-text#:~:text=Alt%20text%20uses%3A&text=Adding%20alternative%20text%20to%20photos,image%20file%20cannot%20be%20loaded.
https://www.lullabot.com/articles/what-heck-aria-beginners-guide-aria-accessibility
Hello, please use the search bar next time π
https://www.sololearn.com/discuss/1733150/?ref=app
https://www.sololearn.com/discuss/1396656/?ref=app
https://www.sololearn.com/discuss/1754221/?ref=app
https://www.sololearn.com/discuss/210820/?ref=app
https://www.sololearn.com/discuss/1384162/?ref=app
https://www.sololearn.com/discuss/1155929/?ref=app
if your image fails to load then the text inside the alt attribute shows up...
the only benefit of it, is to display message incase image fails to load
