To be fair, commercial long-life nickel-iron batteries are already being sold for grid storage. The main reason they aren’t used more widely is they cost more up front.

That’s ok, because they still cost less than alternatives over the full life span of the battery.

The risk is that the higher purchase cost required will likely be wasted as new battery tech surpasses it long before its life is over.

So for now, it’s all about weighing opportunity cost, tech lock-in, and early obsolescence

Syncthing has multiple file versioning strategies.

https://docs.syncthing.net/users/versioning.html

So it can provide quite solid protection beyond a trash can, but yes, it’s still primarily a syncing tool.