To be fair, in place where you need acc, Charis necklace should be substituted by Faith/PCC
I assume you mean Love, not Faith (as a MNK and PUP, a mistake I might make myself out of habit!). I'd add Agasaya's Collar to the mix as well, essentially trading the Enhance DW on Charis for Acc/Atk+8.
Your point is true that you can make other gear changes (and use appropriate food, maybe toss in some quicksteps) to make up for any Acc lost by using a lower Acc weapon.
But still, devil's advocate here... a single Thunder path Kila+2 is 19~20 Acc and good DMG/delay, and if you really wanted to you could use two of em. That's pretty beefy for a single slot. Even Phurba's +10acc is a pretty significant chunk on a weapon that also has the really useful extra effect and still retains great DMG/delay (at least for the 90cap world - we'll see if it gets left in the dust as new weapons and new magian trials arrive, my concern with all of the 89cap JSE weapons).
I personally don't see many reasons it's ever actually necessary to go that Acc heavy on the weapon, and I'm a bit skeptical that 91-99 will change that. Voidwatch may need some acc at level 90, but it's reasonable to think that maybe the initial run of Voidwatch content is built to last a little longer as we get above level 90 (and therefore the acc issues will decrease once we grow into 95/99cap). That's as opposed to the thought that we should expect comparable Acc issues to 90cap Voidwatch today for new content released in the future in a 95/99 cap world. I could certainly be wrong, but I'm taking more of a wait and see approach before I start going too crazy investing time into getting Acc gear that might or might not be completely unnecessary. Plus, if Acc really is that important in 91-99, we just might get some new amazing Acc pieces in future updates anyway... again, I'll wait and see.
If you have some good Acc daggers now or if you've got nothing better to do than make some new magian daggers, certainly doesn't hurt to have them. But is it worth the effort to make new ones now if you don't already have them? Eh... I'd personally say no, with a caveat that maybe it will become worthwhile to have them at 95/99 cap (but maybe it won't, so you might be wasting your time).