bscofield6, to answer your question, not all Iron is created equal. Some iron relics are more desirable than others, but nearly of them are potentially interesting to us relic diggers. The early wrought pieces are the best, but other items such as locks, horseshoes, stirrups, trivets, hammer heads, axe heads, railroad spikes, and others are nice to find as well. Finding iron objects helps reconstruct the history of a site, which I personally find fascinating.
I like coins just fine, but I could ask the same question about coins if we're talking strictly about value- why does anyone keep corroded wheaties that may be worth only 2 or 3 cents, max? If you like coins, why not just go out and buy them? The answer for most of us isn't just the money, it's because we like digging coins. It isn't financially worth my time to go out and dig up a corroded Indian Head cent that I could buy in better condition for $20 from a coin dealer; it makes more "sense" for me to work and take that money to buy the coin. Yet somehow I still find myself whiling away hours at a time in search of coins, and I know you do too. Sure, you might find something really awesome, but you can't bank on that. It isn't about banking, and I think we all know that.
My dug padlock or railroad spike is surely worth more than most of my dug wheaties if I were to sell it, but I wouldn't, because that's not why I hunt relics. Why would I keep a corroded Large Cent that's not even in AG3 condition? The answer is, because I want to. I also want to collect and study old iron.
A lot of us start out coin hunting and then branch out into relics, bottles, gold nuggets, or what-have-you. It's all good. It's cool with me if you don't like relics, I won't be offended. In fact, I'm happy that way. Leave the iron there for someone who's interested in taking the time to document their location and depth, go through the extensive process of conserving them, and piece together the history of a site from them. And while I'm out digging relics, I often find coins anyway.
Happy Hunting,
Chris