As part of its ongoing effort to maximize user engagement, Facebook has added a simple new option which enables users to React to a posted photo or video more quickly.

As you can see in this example, shared by social strategist Moshe Isaacian, the new option enables you to tap and hold on a video or photo to bring up the Reactions bar, from there, you choose the Reaction you want, and apply it, quick and easy, or add a comment.
Here’s how it works pic.twitter.com/lBAJFPEjl0
— Matt Navarra (@MattNavarra) March 28, 2019
At present, you have to go through the extra, strenuous step of reaching all the way down to the bottom of a post and holding on the 'Like' thumb icon to choose a Reaction. This addition will save you the effort - it seems like a fairly minimal addition, but it could be another way to prompt more user responses.
As noted, Facebook is always looking to add in new ways to increase engagement. This has likely been exacerbated by the reported decline in on-platform activity, prompting The Social Network to look to even more engagement options.
On another note, various users have also reported that Facebook's down and upvote option for comments is back for some posts.

Facebook first started experimenting with up and downvotes on comments a year ago, but the tests seemed to peter out, disappearing from most feeds. Now it looks to be making a comeback - that could mean that Facebook has refined its process, or that it's simply re-exploring the potential to boost on-platform engagement.
Either way, as is the eternal case with Facebook, things are always changing, always in flux. Neither of these options is a significant consideration for marketers at this stage, but they could become more relevant, particularly if they do help to boost on-platform interaction.