Are the "Messenger Resting Place" shrines required or are they just a hint system?

[dunbaratu]

I've unlocked 3 messenger "resting places" and thus can now start getting responses from those "shrine" QR squares (the ones with the candles on the sill).

But when I do, the "phantom" blue glowing android "paints" back at me that there's a limited number of messengers left and I should be sure first, and I'm given a chance to confirm before continuing.

I've never confirmed yet so I have no clue what on earth is supposed to happen if I do. I want to be sure I'm not using up some limited resource frivolously, and it seems to be hinting at the idea that using the "messenger" is a limited number of times per game thing.

Is it JUST a hint system and that's all? In other words it just helps teach me something I could have physically done anyway without the help? Or does it actually cause something physical to happen that I cannot do on my own?

If it's JUST a hint system and that's all, then I'd like to try to have a go at finishing without using any of the hints. If it's actually required for some puzzles to be finishable then that's different.

[checkers_of_shalmone]

Confirming it only delivers a one-liner message that may not even help your puzzle. For example, in An Escalating Problem, the hint is You can pick things up from a higher ground which is pointless if you've already done that.

[The Smithybot]

Its just a hint system. You don't need the messengers to 100% the game. The only thing you need them for is a single achievement. They're by no means required.

[Coops]

At the bottom of your HUD you can see how many hints you have accumulated. The max is three with an additional three if you redeem codes from Sigils of Elohim. Using one gives you an achievment but I think completeing the game without using any also gives an achievement.
As stated, the hints are pretty lame. It might help but it also might be something obvious to you that does not help at all.