Please do it.
Especially if you're scaring off would-be players by describing it to them when you haven't actually seen how it works.
They are like dungeons. The quests are like dungeon quests. You will meet characters that you know from the MSQ and find out an additional part of their story and a better appreciation of what happens in Shadowbringers.
And yes, you will need to complete all three
large-scale dungeons over the course of the story to reach its conclusion, just like you have to complete regular dungeons to progress regular MSQ.
Unless you plan to be held up forever and not play the conclusion to Shadowbringers Part 2 in 5.3, you absolutely need to do them and the story is a missing puzzle piece in the narrative for you right now.
To be clear, if you don't know anything about the CT story and you need spoilers (in conjunction with Shadowbringers spoilers) to understand why you need to do it...
...it's your first meeting with the will-be Exarch. He is the central character of the entire thing. You are supposed to recognise him as an old friend.
Really. Just play it. It's not as painful as you think it's going to be.