I think that OP was thinking on something like the currency exchanges you can see in airports or at the corner of the street:
human operator can sell you crypto for price1 and can buy crypto from you for price2.
It's not clear if OP thought only of Bitcoin vs USD/EUR and what other pairs will it have (ETH/USD? DOGE/USD?)
Yes thats the idea.
And yes it will have the more popular or beneficial Altcoins as well.
There are some real-life exchange offices. For example, in my town, you can go to the exchange office and buy or sell BTC in direct trade. Of course, this isn't a very favorable option as they take high fees. You can always use
LocalBitcoins, but be careful because there are many scammers on the website.
Yes that is the idea, as there are lot of scammers, the exchange provides security, comfort and dependability, although to run the exchange and earn profit from it, the fees had to be high.
And I think secondly, the location would matter a lot too? You have to pick a city where there the possible number of crypto users is quite high.
I think that OP might be thinking about regular cantors which we can find on the streets.
But I guess that he might wanted to see cryptocurrency cantors like that available at the city.
That could bring a great results as a business because you would just bring cash to convert it into any cryptocurrency you wish, with a decent rates ( obviously, they would be higher than in online exchange, because of the costs like renting the place, processing costs, etc. ) so everyone with internet connection could have buy their own crypto for regular paper money.
We would not see many scams, because only licensed company could do that, also people would be very cautious to exchange their money in such places like a new-born cryptocurrency cantor.