Hmm... I am wondering why here is only one ebay and why it is not infinitely replicated still. Ask him if you have chance please.
My comparison was Facebook, actually.....and that BTCs value is based on the network effect (hence why LTC, PPC, et al are not worth anything). I agreed with him that current BTC market activity is a bubble (IMO) but that BTCs brand appeal and role as progenitor does give it credibility in the same way that Facebook has virtually no competitors and a massive market cap, so I would not completely discount the network effect.
His problem with this is that Facebook is a company while BTC is simply a means of transferring value whose process can be replicated (a better comparison is Paypal, Moneybookers, Dwolla, Zashpay, WePay, or the other countless payment companies). He asked me to imagine if I would continue to use Paypal if I had to worry about enormous exchange rate fluctuations.....or to imagine if to make Paypal purchases I had to buy and sell its stock as a means of transfer......and he asked what problem BTC solves for the average person.
I confess, all this sudden awareness is partly my fault. I'm constantly commenting on articles I see online, posting on Facebook, tweeting, etc. Today I commented on a couple of articles about the Fed, saying: "Dear Fed. You really blew it, so we're taking back control of money. You can keep what's left of the dollar, as we're switching to Bitcoin. Let's see you try to quantitative ease that!"
I've even ordered some Casascius physical bitcoins to give away to the groomsmen at my upcoming wedding. I'm not sure they will appreciate them now, but when I tell them that a version 1 Casascius coin recently sold on eBay for over $500, I'm sure their interest level will rise a bit!
But getting to your question, what problem does Bitcoin solve for the average person?
It solves two big problems. First, it will eventually become a stable currency free from government abuse. Once it is widely used around the world, it will stop the politicians and central bankers from tinkering with the economy by manipulating the money supply.
Second, much as email made handwritten letters virtually obsolete, Bitcoin will eliminate many of the functions (and costs) of banks. You can send any amount of Bitcoins (that you own) to anyone, anywhere in the world, any time of day or night, for a fee of about $0.05, and the transfer will be confirmed in about an hour. No longer will you be forced to choose between checks or ACH, which take days, or wire transfers that cost $25-50 and only work while the banks are open.
Bitcoin is Money Version 2.0. It's easier, faster, and cheaper to use than fiat. In fact, because it is free of government manipulation, it is perhaps the most important technological innovation of our age.