Earlier quoted context omitted.
"because I can, and it is fun." The best answer! I am most of the way done with upgrading most of my homelab to 100G from 10G, but there really isn't a practical reason for it. 100G has dropped in price so much as datacenters are all about 400/800G now.
Nice! Cool to hear from a fellow admirer of overkill-lan setups ;) Which cards do you prefer for 100G, and what is the situation with dacs/optics?
Frankly, 10Gbit is fully 25 years old with, 10GbaseT being 20 years old this year.
Thats ridiculously ancient technology. There is/was a 25/40GbaseT spec too (now 10 years old), which basically no one implemented because like ECC ram (and tape drives, and seem to be trying to do it with harddrives and GPUs) the MBA's have taken over parts of the computer industry and decided that they can milk huge profit margins from technologies which are incrementally more difficult because smaller users just don't matter to their bottom lines. The only reason those MBAs are allowing us to have it now, is because a pretty decent percentage of us can now get 5Gbit+ internet access and our wifi routers can do 1Gbit+ wireless, and the weak link is being able to attach the two.
I did a bit of back of the napkin math/simulation about a possible variable rate Ethernet (ex like NBbaseT, where it has multiple speeds and selects faster one based on line conditions), and concluded that 80+Gbit using modern PHY/DSP's and high symbol rate, multiple bands, techology which is dirt cheap thanks to wifi/bt/etc on fairly short cable distances (ex 30-50M) on CAT8 is entirely possible. And this isn't even fantasy, short cat7 runs are an entire diffrent ballpark from a phone pair, and these days mg.fast/etc have shown 10Gbit+ over that junk.