Yes it is a minor issue for you and obviously someone must be foolish to point out a glitch in a supposed "benefit".
I would wager that it is a minor issue, if an issue at all, for most players. And if it isn't a minor issue, then they've got more problems than these quests.
Yes, there are work arounds that can be employed to avoid this new benefit.
I use no "work arounds". When a quest asks me to "spend x Tavern silver", that's what I do. If you consider using it for an upgrade rather than a boost to be a "work around", then you're reading more into the quest than what is there.
It's commendable that some have pointed out ways to overcome this benefit, but overcoming a benefit doesn't sound like what the developers thought they were creating in an otherwise useful mechanic, the Castle.
Overcoming a benefit? Way to look at it, Eeyore. Do you honestly have such a shortage of Tavern silver that this is even a minor inconvenience? If so, then this "glitch", as you call it, is the least of your worries. Not to mention that you have no idea what the developers are or were thinking. You're projecting your thought process onto them with no information to support it.
I do believe INNO does care about its content and as foolish as it may seem, inconsistencies or unintended consequences should be pointed out.
How is it an inconsistency? What is it inconsistent with? Is there another game mechanic where a boost lowers the cost of something and quests were adjusted to account for it? Not that I'm aware of. And, again, you have no idea if this consequence is unintended. Theoretically, this could be Inno's response to all the complaints about loads of Tavern silver with not enough to spend it on. You don't know, and neither does anyone else here.