Lots of companies do exactly this. For example, in Japan, where I live, the train and bus companies will give you a card. You can "put money" on the card and then spend it on travel. You can also use the cards to buy things in the convenience stores, some restaurants, vending machines, etc, etc.
You can think of this as a "coin" that's pegged against prevailing currency (in my case, the yen). It's not a "cryptocoin" since there is no "crypto" involved, but as there is barely any "crypto" involved in cryptocoins anyway, I think that's a bit of a moot point.
There are problems with this model. First you have to trust the central authority with your money. They could do a runner and there would be nothing you could do about it. In fact, when I lived in the UK, I discovered that London Transport often mischarges - it forgets where you "tapped in" or "tapped out" and charges you the maximum possible charge for your journey. In order to get your money back, you have to register your card and apply within a specific time period to get refunded. If you don't know the procedure, don't want to give out your person information, don't realise you were mischarged or wait too long -- sorry, your money is gone (Really big piece of advice for anyone using an Oyster card: Register it and check the charges every day. Unless things have gotten better in the last few years, I'm sure you will be extremely surprised at the charges).
The problem here is that the payment processor has all the power in the transaction. They can just take your money if they feel like it. Also, they can refuse to pay for things if they feel like it. Finally, they are a single point of failure. If they have technical (or financial!) problems, then you may not be able to spend your money.
Whether or not you assume initiatives like Bitcoin were started as a scam, the implementation potentially solves a lot of the problems of these payment processors. Importantly, if you put your coins in a central exchange you are right back to square one! No amount of crypto goodness will save you from the exchange shenanigans because they control your wallet.
This is why things like the Lightning Network are interesting. It allows for centralised payment processors, but with distributed guarantees about who owns the coins and where and when they can spend them.
I find it incredibly unfortunate that "cryptocoins" endure such incredible hype and involve so much real (and imagined) money. So many power plays, so many scams, so much FUD. But at the centre of it, these are interesting real problems. Once the dust settles it will be quite nice to see what useful results actually emerge.