Many people believe running fibre between buildings, even in ducts, is safer than running copper because you get opto-isolation from lightning.

The second thing is that domestic buildings usually do not come with a consistent ground plane. I worked in a 1960s build purpose made for mainframes and we had ~48v floating between racks at either end of the building and had to do a shitload of work to reground the building, in the 90s (-we were decommissioning an IBM 3033 and deploying a secondhand cray1) the point being somehow, God knows how, prior rs232 serial wiring didn't care and the ground plane for the mainframe was fine at the time. Pre Ethernet this stuff maybe just passed code.

I suspect people who build their own home to some spec acquire these theories. Data comms? Not much reason tbh unless you're pushing a lot more data than normal.

It's one of those "just because" moments. The idea was to future proof my home infra for a 25G NAS connection. Most ethernet connections tap out at 10G. While theoretically speaking Cat 8 cables can do 40G, hardware support for full 40G Cat 8 NICs is rare. Fibre is very very flexible with its potential bandwidth and SFP28 transceivers are relatively affordable (if you don't do what I did by using SMF. Home networks should only use MMF if the property isn't a mansion.)

10GbE rj45 (normal ethernet jack) spf modules tend to burn power and get extremely hot, like to the point of burning you if you touch it - the manual for my switch said to leave adjacent ports unoccupied if using one of those. The fiber ones run cool to the touch.

Also, not needing to rerun any cabling if we want to bump up speeds in the future, you just change the laser module on either end. These should be good to >100x current speeds. Not the case with copper.

10G is looking to be the end for twisted-pair copper.

25GBASE-T and 40GBASE-T were standardized 10 years ago, but there are still basically zero products available with support for it. The datacenter market just wasn't interested and chose to use fiber and DAC instead. Worst of all: it requires Cat8 cables and is limited to 30 meters. This means it can't reuse existing cabling, and doesn't have the reach for many home applications - OPs blog post mentions the longest run in their apartment being 55 meters.

Combine that with the general death of wired networking for home & office use, and it is extremely unlikely the market of hardcore tech enthusiasts is big enough to warrant massive investments into developing some kind of 25G-over-Cat6-for-100m standard.

10G is pretty much the standard for high-end gear these days. This means any kind of future-proof setup needs to be prepared for a future upgrade to a fiber-based technology.

Ethernet can be run over copper or fiber cabling, it's not an alternative to fiber networking. Assuming you meant what's the advantage of fiber over copper: you can use faster speeds, longer distances less power on fiber plus it's not electrically coupled.

(speeds: 100 gig today, but faster speeds are coming.)

They get less hot (especially the network adapters on the ends of them), can go a lot further, can be a lot denser (including being able to carry things other than Ethernet in the same bundle), and are a lot more future-proof (unless the cable jacket literally crumbles at the slightest movement in a few years).

If they're using spf+, it's almost certainly ethernet on the fiber. Do you mean, why not use copper twisted pair?

Ethernet runs on many mediums, as well as over the ether.

I kinda want some just 'cause it's cool, with the only problem being that I haven't been able to find an excuse to justify (to myself) needing it.

Also much lower power and heat.

For me, it was for a nearly 100ft run that try as I may to get a good termination, I'd often find my Mac Studio and Ubiquiti EdgeSwitch struggle to negotiate at more than 5gbps. So I got a smaller switch upstairs, ran 10GbE to it, approximately 10ft, and then ran OM-3 fiber for the 100ft up into my attic, across my house and down into the garage. Rock solid at 10 Gbps.

Server-grade fiber optics can get to terrabit/sec speeds. In other words, ludicrous speed.

(He’s gone, plaid!)