I'm in full agreement with this recommendation!
I actually only got into the Echo project games around July when Arches was in Build 2, but it was the game that hooked me on the concept of Echo.
I went into Arches with no prior expectations, so the opening blew me away and made me so curious as to what would happen next. It is really interesting to see the town of Echo in the aftermath of whatever happened in the game Echo, and wonder... What happened?
I then went back to Echo (the game this time) and checked it out and enjoyed it thoroughly, but Arches still has my highest hopes and expectations and IMO still works as a good jumping off point.
However if you prefer there are a couple of other options for how to play the games:
1. Chronologically (In Universe): Start with The Smoke Room (TSR), go on to Echo, and end with Arches. I wouldn't really recommend this as both TSR and Arches are in development so this will be jarring jumping from the middle of TSR into Echo with no clear path to explain how one leads into the other yet (though I assume it will clear up as development progresses). Another issue with this is that both Arches and TSR expect you to have read Echo and mention some items that lead into speculation about how everything ties together.
2. Chronologically (In Real Life): Start with Echo and get a decent baseline for what can occur in these stories. You can supplement it with Route 65 (Highly recommended after Leo's route in Echo) and Benefits, both of which are short reads. From there you can go on to either Arches or TSR, though it is worth mentioning that TSR has a lot more content due to being further along in development. Both are interesting as they both act as sequels to the game of Echo, but act as prequels (TSR) or sequels (Arches) to the events that occur in the game.
3. Reverse Chronology (In Universe): I accidentally played this way, but it works really well to build up suspense and raise the tension of the mystery. In Arches you see the aftermath of whatever happened in Echo and wonder what possibly could have happened. In my playthough of Echo I could only wonder how this small town leads to the horrors I saw in Arches as I went through the everyday lives of Chase and his friends. And then the horror in Echo hits and it starts to explain some of the horrors that Dev and Cam go through in Arches. After completing Echo and Route 65, I moved back to TSR and have enjoyed seeing how the seeds of what happened in Echo and Arches were laid over 100 years ago and see how things could have shaken out differently.
TLDR: I totally agree with Drago, but hey it's fun to think of different reading orders for these novels, kinda like Star Wars watch orders. :)