I looked into the actual reasoning here:

- Originally, IETF specified .home, but never went through the process to add it to the list of reserved names.

- Someone applied for the .home gTLD, and while it ultimately didn't go through there was a while while it was up in the air. Due to this the homenet working group had to change gTLDs.

- They decided to switch to .homenet. However, because of DNSSEC, whatever they used would need an insecure delegation in the root zone or validating resolvers wouldn't be able to resolve it. Since IAB controls .arpa but IANNA controls the root and there was no process to ask IANNA for this, they eventually decided to use home.arpa instead.

https://mailarchive.ietf.org/arch/msg/homenet/8cfJkr7SPMaPS4...

RFC 8244 is an interesting read on the topic: https://datatracker.ietf.org/doc/rfc8244/