I don't believe anything Bout this will change at all.  Yes, bitcoinget are probably here to stay, but fiat isn't going anywhere for a very long time.  And as seeing as there are millions of coins in this world, probably billions, it is bound that a huge number will be lost in the sand, dirt, etc.

Well Casascius coins is a possible solution, but it's not the same though. The thrill to find a rare and limited edition coin is always the best experience. In most countries these Casascius are not allowed,

and it's not in general circulation. The idea that someone traded on a daily basis with the coins you found, makes it just so much more...how should I put it? ....Romantic. 

In any way, I will still miss these finds, when we go fully digital. 

If we ever go fully digital, I don't think there will be a shortage of physical coins anytime soon after that.
Mints make a sh*t ton of coins that would put classical-era pirates to utter shame. Numbers range in the trillions of coins out there. A quick search will do.

I think treasure hunts are exciting since the rarity of such old coins are exciting in itself. I'm not sure how many coins are there in circulation during the 1700's, but I'm sure modern coins outnumber them by several orders of magnitude, hence the rarity. It should make hunting for modern coins simpler since one does not simply tuck away 11 billion coins under a pile of dirt.

I will miss. But the question is How bitcoin can replace Fiat? In bitcoin we need bitcoin wallet and internet to do transaction. In fiat you need only fiat and it is easy to pay. I think in my opinion Bitcoin Cant replace fiat even if bitcoin is known world wide. And I want to add  that if bitcoin is our fiat in future do you think government will allow this ?

That's a foolish dream. Bitcoin won't replace any form of fiat, not at least of the Bitcoin we know today. Technical restrictions everyone in this forum should be very aware.
Not to mention how payment processors will always exist to prevent scam(or to cause them, like with PayPal disputes) and act as a middleman, which wouldn't make any difference if it's BTC or USD.

iam not believe if bitcoin replace to fiat money
fiat money flat rate bitcoin is anonymous not only one people control price bitcoin, price up or down only comunity disecion
so no control anonymous very dificult is one people one company control price bitcoin

^^^ Warning!
This user is simply a shill account for the
'cloud mining' ponzi scam he promotes in
his signature.


Well metal-detecting isn't usually about searching for coins still in circulation, so it'll be quite some time before it is even affected by crypto-currencies.

Well, even at this generation there are less and less people having this treasure hunting experience with metal detectors. Simply because this generation of youth is obviously highly uninterested in doing such things now, and another reason probably is because there are less treasures to hunt (although I admit there's still countless of them to be found).