why are silk heart where they are?

im kind of lost about why silk heart are where they are and what they symbolise

like, okay, lace giving you one make 100% sens. she is a silk being. (and even then, wouldn't it kill her if you steal her silk heart? why doesn't phantom give you one too as she is a silk being too?)

the conductor? eeeeeh, i see why he would give you one as you just defeated like, a pit full of silk and shell

but bell beast? from a gameplay standpoint i get it: you want an item you need to do any platforming to no be missable. but wouldn't it have made more sens to give it to widow especially as she is one of the few unskippable boss?

and why just 3? is it just to annoy spell build? idk, they feel verry uninteresting, especially as they are far from evenly paced, nor do they give you any real power boost.