For the same reason you shouldn't rent or buy or use a backhoe when it's a shovel of dirt. For the same reason you shouldn't stand up multiple 8U rack mount servers to run your homeassisstant instance that would be happy on a raspi zero.
I would love it if web devs would stop externalizing the costs of their bloated apps onto their users. Make web devs care about resource utilization. How much bandwidth, electricity, and time is wasted on poorly written applications?
More like you shouldn't use a backhoe and charge passing people for its fuel and put your backhoe in the middle of the walkway. It brings negative value to the end user. If you don't care for your end user - fine, but then you can't expect them care for you or your product either.