I'd say I prefer my windows to just *be gone* when I minimize them. I know they end up in the system tray. I don't need an animation to tell me that my UI/Desktop Manager is doing its job.
You can provide status information visually WITHOUT animation.
Just to say: Some years back, I had a boss who, using a dual monitor station for software development, frequently hit the Windows 2000 Window Limit (64 I think).
I currently have 22 windows open. Of them, about 8 are tabbed browser windows so you can figure I likely have about 60-80 tabs open concurrently. My editors and PDF viewers also run multiple documents concurrently. I'm not even on heavy workload right now or there would likely be another 10-15 windows open. I sometimes do notice slowdowns but I suspect I may be pushing the available memory from time to time, but animations may also play a role.
In the background or actively running on my machine, I have 2 Tomcat instances, and HFS instance, iTunes, SQL Server instance, a My SQL Instance, Apache Instance, Netbeans, Eclipse, KeePass 2, Adobe Chrome, IE, SVN client and server, Steam, Calibre, and the list goes on. There are likely a number of background servers I'm actually forgetting.
I begrudge my cycles to animations I don't need and that actually I find visually distracting and which don't aide me in figuring things out but I find distract me and confuse the issue.
Not everyone just has a handful of apps open. Not everyone benefits from animations. A lot of $ are used getting them to work and making them pretty when that money could be spent on truly functional software features.