Why the builder requests books (and wood) instead of bookshelfs?

And are there any reasons why the builder won't place item frames (with items in it)?

the builder should definatly use the block in the world instead of it's drops, there could be an override registry where substitutions could be registered for custom itemstacks needed to place special blocks

This is most likely going to be fixed for 8.0.x

It requests wood? From my tests it only seems to require books. (Tested with a new blueprint in 7.2.x dev)

You're right; I did some miscalculation...
What about the item frames?

Support hasn't been added for them yet

Why don't you change the code so that the machine just expects the very exact block as it is found in the recipe?
For items like item frames (once implemented) and torches and flowers it'd be nice if these were not placed before the block they are planned to be attached to

Yeah ok thats dumb as stone requires cobblestone rather than actual stone. I don't even want to know how badly you could exploit this with enchants.

And torch placement is broken. WHEN DID THAT BREAK :(

Tested In BC 7.2.6:
Can confirm the builder requires books instead of bookselfs and cobble instead of smooth stone>
I was unable to confirm that builder was unable to place item frames as it was able to place item frames for me:

The builder was also able to place torches for me:

Were the wooden planks there before you started the torch blueprint?

ah, yes they were :/

@AlexIIL from @rapus95 comment:

For items like item frames (once implemented) and torches and flowers it'd be nice if these were not placed before the block they are planned to be attached to

The same also applies to wooden trapdoors. I was using them in a blueprint before and they are placed before the blocks they are attached to...