I'm tempted to get one and set it up as some kind of cache in my NAS. I'm already in silly territory with it now, anyway. 1GB/s of writes sounds crazy though - I haven't got anything that can write to it that fast!
I have a PCIe NVMe card (with a Samsung 950 pro M.2 in it) in my home server, which serves as an L2arc device for a ZFS pool. It is pretty nice. Runs a bit warm though.
I think that a home nas would have a lot of async writes and very few/none sync writes. So a ZIL dedicated device (the SLOG) is not really useful/helpful. I'm not sure even if you really need an L2ARC device, just slap 8/16Gb of RAM on it and you will be happy...
Obviously if you are playing seriously with VMs and databases and whatever else both of those (SLOG/L2ARC) may become important for you, I'm going for the "i'm just using this to store my raw-format photos, backups for the taxes and other big files" kind of usage here. :)
We have been primarily using Intel NVMe storage for our database servers since fall of 2014 with no major complaints. Our high end desktop/laptop systems are also using the latest Samsung NVMe M.2 drives which are screaming fast.
We do want to minimize that--compute costs money, and storage is irreducible. But you can only reduce aggressively if your larger distributed system is great at repairs, since the failure of a single box kicks off 1PB of repair activity!