Shikantaza here. It's a big deal.

Consider:

We all know about "paying attention". Pay attention in class. Pay attention to the movie you're watching. Pay attention to where you're walking. Etc. It's important and we do it all the time.

Take that to the next level. Pay attention to a thing for a while. AKA Concentration. That's important too. Deep thinking, careful doing, science, engineering, art. It's necessary for all that.

And then there's meditation. It's more stuff to do with your attention.

Samatha (AKA concentration meditation) is concentration taken to the next level. All that deeper thinking etc that you got from concentration, this takes it further. Possibly much further. There are weird depths. And also, you become very familiar with the ways of attention. How it moves and how it affects the rest of your world and what you can do with it.

And then there is Shikantaza (AKA formless meditation, meditation without a seed...). it's a hard left turn. Serious sci-fi. I'll leave it at that.