They don't; they only help Instgram "categorize" your posts.
To verify the CEO's statement, analytics firm Social Insider studied over 75 million posts published between 2021 and 2022.
The firm verified that using a lot of hashtags, indeed, is a time-waster. They don't boost readership.
At best, the use of a few—six or so—will help make your posts "discoverable."
But piling them on is futile.
Why is that?
Instagram has changed its search engine.
Users can now enter keywords, instead of hashtags. That means many avoid the hashtags page, preferring to look only at search results.
Should you drop hashtags altogether?
No, says Social Insider.
While readership of your post isn't improved by the use of hashtags, the inclusion of six or fewer hashtags will improve Instagram's ability to categorize your post.
Using more than six penalizes you.