A litter pricey, great concepts. For me I will just use a rpi4 with two usb drives for a poor man NAS, that just backup stuff and nothing more, I can do it with less than $60(including housing, 2GB version, fanless)
I agree it is a little pricey for something that doesn't come complete with the SOC. I would rather use something like the ODROID-HC4[1]. It isn't as fancy as this or have as broad of support as the RPi, but it is $80. 1: https://ameridroid.com/products/odroid-hc4
On the other hand, you can have a USB3.1 hard drive docking station(around $30 for 2 hard drives) to hook into any cheap SBC board that provides a USB3 port. another way to do poorman NAS.