Hardened valve seats - do they really matter?

I will tell you what the machine shop guy told me when I sent some J heads in. He said "if you are daily driving it yes install the seats if you are car show cruising it they should last as long as you cruise the car" the as long as may be a reference to my age I'm in my 50s...Im not arguing whether the guy is right or wrong but I agreed and didnt have the seats installed. . A car show cruiser for me may see 1500 miles a year, and Ill throw the lead additive top cylinder additive in for good measure...also doing everything 100% just makes it better for the next guy who low balls you at sale time I like to leave some of the fun for them...:)