Hardened valve seats - do they really matter?

Times are changing for sure. Not as many people rebuilding these older engines. The newer stuff LS for example runs longer then the entire vehicle is scrapped.
I typically took a few heads of whatever I was building to the machine shop. They would take the best ones and install hardend seats. Not sure I would have noticed the difference. Cost wise I did.
It is interesting how far some of the old heads valves would sink though. Well pass the hardened surface. Wonder how much better a hardened seat head would hold up under the same circumstances.
Regardless of wether you choose hardened seats are not it's nice to have the option. A few machine shops in my area have closed. A bit of a bummer as it may be an indicator of times changing.