You're missing the in-between from the mystery and the reveal. Its like schrodinger's cat. In the player's perspective, its both a trap and a reward until the mystery is uncovered. The way a party processes both those possibilities discern whether or not they want to engage and how they engage.
No, I get that. But what you are missing is that if the only point of the door is to obscure what lays beyond, then the door isn't super important. You develop an SOP for dealing with the majority of possible dangers behind the door, then open it.
I've been in a game where we had dozens of doors to open back to back to back... we lined up the same way every time. To the point where if it wasn't a virtual table and we had to tell the DM, I'd have gotten annoyed, because it was the exact same formation and the exact same commands every single time. And there is no value in that. It's just repetition.
Assuming the book is a physical item and not some abstract improvised object created to punish players, there actually is more you could've done with the book to prevent yourself from getting hurt.
For instance, investigating it for traps. You have to tell the DM what you do with new information because its your character and what you do may not be obvious. You could decide you don't want to read the book. Maybe you use a spell or feature to read it without touching it. Perhaps you tell everyone to step aside so they aren't in a blast radius. Maybe you pour water on it.
What you think is a logical step-by-step scenario makes assumptions on the player's end.
Yeah, and sometimes you should make assumptions, because the player's are.
An actual real-life example. We were playing Dark Sun, we were working for the Sorcerer King and we had been tasked with going out into the desert and seeing what was going on with this ruin that was about two weeks out or something. So, we say that we head out.
About half way there the DM says we run out of food and water. We all ask "What are you talking about?" See, we assumed that as people who live on a desert planet, and knew we were going on a month long journey into the worst part of the desert, on the orders of the government that we were a part of, that we would have requisitioned supplies for the journey. The DM's response was "well, you didn't say that."
So, we had to travel back, the DM had to homebrew rules to allow me to burn gold to use the Create Food and Water Ritual (4e DnD, by the way) so we could live long enough to make it back, to be berated by the Sorcerer King for being so incompetent for not requisitioning supplies.
So, at some point, there is a choice. Either the players have to make a checklist, declare they check for traps. Declare they clear the area. Declare that they pour water on it. Declare that they run a magnet over it. Declare, declare, declare...
Or the DM can provide the information to make a decision. Maybe when I see the book, I see the glowing rune indicating it is trapped. Now, instead of me just blowing up, I have to decide how to deal with it. This is a far more interesting aspect than waiting and hoping I personally think of every possible thing I should do to find out there is something to engage with.
Great. And that hooked stick gets latched onto a trip wire and activates the trap. Hurray! But now the corridor is filled with blades and flames and noxious gas and it has a sharp right turn so you can't even reliably teleport to the other side.
Maybe it wasn't a good idea to trip everything...
And these are the reasons why having a "one-size-fits-all" solution simply doesn't work as well as one may suppose.
Great. This is awesome. Now we can wait for the noxious gas to disipate and start dismantling the traps, and the Rogue didn't get hit with noxious gas, flames, and swinging blades from a single trip wire.
Or, hey, maybe after a few minutes all of those traps stop going off, and since we now know where the trip wire is, we can step over it.
How is any of this a bad thing? This sounds like a great outcome.