What I liked about the acorns was that they were very affordable (ie. ~$200), were an fpga, and used very little power. I see other FPGAs around $5000 but simply cant afford them. I am a hobby miner.
Acorns were developed as GPU accelerators to improve GPU mining by working together with them. Unfortunately, the software for this purpose was never finished (for various reasons), and now they can only be used to mine few algos. I think they sell for less than $100 used now.
Have a look at their official discord to find out more about the current status of its development: https://discord.gg/SeZ3shJ