Separating the internet-connected (and therefore low life-expectancy) bits from the analog sound-reproduction (and therefore expensive and high life-expectancy) bits is a great way to build a solid system that can grow and adapt over time.
This is a super cool and gratifying way to deliver the internet-connected bit at low cost (at least for those with hardware inclination, and access to means of production). For those without, Sonos' Port product does a great job filling the same niche. Though at $450 its a ... multiple ... of the cost of the project presented here!