This could be interesting. According to a new discovery by reverse engineering expert Jane Manchun Wong, Facebook is experimenting with new color highlighting for hashtags and profile tags within post text.
Facebook is working on displaying hashtags and mentions in the “new Facebook blue” color pic.twitter.com/G1r0DjLLNm
— Jane Manchun Wong (@wongmjane) February 18, 2020
As you can see in Wong's tweet above, the tag and hashtag here are both highlighted in Facebook blue. For context, here's a post with a tag and a hashtag in the current format.

The blue highlighting would certainly make them stand out - but is that a good thing? Would that get more people tapping on either, and generate more engagement?
In a social media marketing context, the value of Facebook tags and hashtags is somewhat questionable - various studies, for example, have shown that hashtags simply don't work on Facebook, or at least, they don't significantly boost engagement with Facebook posts as they can on other platforms.

That's not definitive, however, and it is possible, given that Facebook facilitates some 2 billion on-platform searches every day, that there is some benefit to adding in additional discovery elements where you can. As you can see in the example above, we at SMT do still experiment with Facebook hashtags in some of our posts, but we haven't seen any significant benefit from including them in our limited research.
Profile tags are similar - while tagging another Facebook profile does provide the key benefit of letting the other party know when you've mentioned them in your post, the additional reach or engagement benefits, outside of that, are not clear.
Facebook did announced back in 2014 that:
"When a Page tags another Page, we may show the post to some of the people who like or follow the tagged Page."
So there is, theoretically, an additional reach benefit to tagging other Pages and profiles, as it may see your content shown to the audience of that other Page/person also. That means that in addition to being good practice in acknowledging your sources and partners where you can, there is added potential benefit - which, by extension, could also mean that highlighting such more clearly within posts, that could lead to more clicks on those links, and therefore more traffic to each, more engagement, etc.
Maybe.
It's difficult to consider the balance between what some will see as 'uglier' posts versus more obvious links, but it is likely worthy of an experiment - and it's worth noting that both LinkedIn and Twitter highlight tags and hashtags in this way already. Facebook might, in fact, find that by highlighting such more clearly, it leads to a lot more engagement with tags, which could make both a more significant consideration moving forward.
But that's only if Facebook does move ahead with the test. At present, this is only an internal experiment, and we've had no word about a live trial at this stage.
It could be an interesting one to watch - and if Facebook does eventually roll this out, that would likely suggest that it may well be worth adding hashtags to your Facebook posts again, as their initial results must have shown increased tag engagement as a result.
It's not a thing as yet, but this could be worth monitoring if it becomes a full test.