IMO, it's not that .22Hornet, .30-30, and .45-70 aren't "mainstream" so much as some people who don't shoot those rounds have an impossible dream of seeing them die out. These are three good older cartridges we need to keep around.
.22Hornet is quieter than .223Rem/5.56mm and, from what I understand, good to 200yds while using the same bullets as .223. My understanding is it's economical to handload and got a lot of folks started handloading back in the day.
.30-30 is a great round with round-nose softpoint bullets. Load spitzer SP's special for that single shot and you can stretch the resonable effective range another 100yds. Best deer cartridge of all time IMO.
.45-70... what needs sayin'? You can custom load for this one easily too. Load you up some 405gr LFP's over 12grs of Unique or 18grs of 2400 and go for it. Be sure and use a piece of tissue paper over the 2400 though... according to some of my range buddies, 2400's a bit more position sensitive and needs to stay back on the primer for uniformity of pressures.
No, I think this is a great deal and if I were looking at it, it probably wouldn't take me more than about 5 minutes to make up my mind. BTW, some might say an individual's age has something to do with it... I'm 33 and I seem to disagree on this stuff with a lot of guys my age.