The switches eventually fail, but most mice use the same Omron switches and they are easy enough to replace if you know how to solder. The teflon skates wear out too, but you can find replacement for most name brand mice online.
You just need a program that actually supports the hardware video decoder. I've played 30-40mbps bluray rips on a Raspberry Pi 1B without any issues in kodi. The video played smoothly with no frame drops. The user interface was very sluggish though.
The GPU and video acceleration on the Pi is weird, so software has to be built specifically for it.
Make sure you get the flash drive from a reputable seller. Sites like amazon have lots of fakes that are actually a much lower capacity than they report.
GPU support is a real mess. Those ARM SOCs are intended for embeded systems, not PCs. None of the manufacturers want to release an open source driver and the blobs typically don't work with a recent kernel.
For ARM on the desktop, I would want an ATX motherboard with a socketed 3+ GHz CPU with 8-16 cores, socketed RAM and a PCIe slot for a desktop GPU.
Almost all Linux software will run natively on ARM if you have a working GPU. Getting windows games to run on ARM with decent performance would probably be difficult. It would probably need a CPU that's been optimized for emulating x86 like what Apple did with theirs.
If you don't release your source code due to security concerns, you just announced to the world that your software is vulnerable and you're relying on security through obscurity.
To use secure boot correctly, you need disable or delete the keys that come preinstalled and add your own keys. Then you have to sign the kernel and any drivers yourself. It is possible to automate the signing the kernel and kernel modules though. Just make sure the private key is kept secure. If someone else gets a hold of it, they can create code that your computer will trust.
They are just trying to leech out as much money as possible before the go the way of Digg.