They spent money on Barges they needed for a show, im not sure how that is wasteful.
Just because something has a use does not mean that it isn't also wasteful. The two are not mutually exclusive.
Watching Harmonious, it's not really clear what purpose the barges serve. Yes, the video boards, fountains, and moving arms are used in the show, but there's really nothing in the show that is so unique and specialized that it couldn't have been created in a different way. Unlike the earth barge in Illuminations, the dragon in Fantasmic!, or even the kites for the lame KiteTails "daytime activation", there's nothing to imply that this infrastructure was purpose-built for this show. It was incredibly expensive, but isn't utilized in a meaningful way.
I'll use Everest as an example once again, not because it was a low-budget creation, but rather because of its extravagant spending. The yeti AA is a perfect example of wasteful spending: millions and millions of dollars were poured into a figure that could only be seen for a couple seconds of ride time. Even when the ride was brand new and everything worked perfectly, it was a blink-and-you-miss-it moment that was over in a flash.
The same impact could have been made with a far cheaper figure that had a more limited range of motion; perhaps not as limited as the old Abominable Snowman on the Matterhorn, but not as complex as what got built. Guests speeding by in a dark cavern can only process so much in the 5 seconds that it's visible. In addition to saving construction costs, it almost certainly would have been a more reliable long-term solution with easier maintenance, to the point that its malfunction wouldn't be one of WDW's greatest ongoing embarrassments 15+ years later.
I know that many people online like to denigrate "value engineering" as a simple cost-cutting measure, but that's not what it is at all: it's a way to ensure that the money you're spending is being used wisely. Is this function necessary? Is there another way to achieve the same goal that's less expensive? What are the lifecycle costs of the proposed solution? Are we being good stewards of the money we're given? Is there a way that we can get more for less?
Many classic Imagineering tricks rely on fooling the eye into thinking there's more there than was actually built: it's the limited-motion figure that you pass so quickly that you think it's fully articulated; it's the window in the background, implying a world beyond the immediate scene; it's the painted flat backgrounds that are out of focus enough to make you think they're fully dimensional. It's like a striptease, keeping you interested in what's just barely out of view, inviting you to imagine a world of possibilities. These are the parlor tricks on which Disney Parks built their trade, and which are being sadly forgotten in the day of endless "immersion" where every element is elevated to a starring role and the backgrounds are devoid of detail as a result.
In the case of the Harmonious barges, it's not really clear what their function is, or why they were built the way that they were. The arms flail around during the show, but don't have any real purpose. The fountains aren't especially expressive or impressive. The central ring is dark for a huge chunk of the show, can't be seen from the majority of the viewing areas, and has no reason for its shape or size. The lighting systems and video boards are fine I guess, but there are countless other ways to achieve those elements that are less obtrusive during the day. Even though all this was built specifically for Harmonious, the show doesn't feel like a natural fit for the unique infrastructure.
In many ways, the show feels like it was designed around existing infrastructure that was left over from a previous show, rather than one designed from scratch with custom-made equipment. And for a very expensive purpose-built show that ruins daytime sightlines throughout the most scenic parts of the theme park, that's quite a damning indictment.
I have no reason to believe that the Guardians coaster will be any less wasteful; in fact, with its massive budget and physical footprint for a single attraction, it seems even more likely.
