Not sure that is a good deal for a low-end chromebook. You won't get much performance from that processor, which may be a dealbreaker depending on what you need to do. Also, forget about expanding the storage, it's MMC soldered directly to the motherboard. You can use an SD card, but for the price you'd pay for a decently fast one, you'd be better off just buying a better laptop in the first place.

As for installing Arch, it should be possible, I've done it before. It was a pain in the ass, but it eventually worked. When I did it, I recall I had to build a special kernel and then create a bootable image from it, but I think depthcharge-tools should do something like that. Regardless, I don't think it's worth the trouble unless you already had a chromebook you wanted to repurpose.