At a recent speaking engagement, the question was posed about using hashtags on Pinterest. Do they work with the new format?
The answer is “yes” and “no.”

If you are asking if hashtags work as well as they do on Twitter, the answer is “no.” When you search Twitter with hashtags, the search results come back with the most recent tweets pertaining to that hashtag. Using hashtags on Pinterest has never worked this way.
On the old format, you could use hashtags to search but the results would include the pins with the most interactions first.
Now, the new format has changed your ability to use hashtags even more.
How hashtags work on the new Pinterest format
If you place a hashtag in the search bar on Pinterest, your results will be the pins with the highest level of engagement with that word in the pin description whether or not it contains the corresponding hashtag.
For instance, consider this image where I search for #homeschool:

Now, if you are browsing Pinterest and you spot a hashtag, you can still use it as a way to quickly search for pins on that topic. Just click the hashtag and it will automatically search Pinterest for you.

So, in the traditional sense, hashtags do not work but in a technical way, they do. Just depends on what you want them to do.