In principle, it is possible to imagine. People would not have to stand in line for the exchange, the purchase would be easier. But when there are other cryptocurrencies in different areas, it becomes more convenient and faster.
Everything is possible to imagine, even flying pigs and green aliens on Mars.
Multiple cryptocurrencies aren't more convenient to use than a single unified one, just as multiple fiat currencies aren't more convenient to use than one. Would it be faster? Nobody knows that. In 2010 nobody thought of segwit or LN. If BItcoin was to be used as a primary payment option at its current state it wouldn't be able to handle all transactions, but 10 years from now it will be much faster.