It isn't necessarily better to have dozens of different currencies, but it is better to have the ability to issue your own currencies rather than be dependent upon a single monopoly which may (and does) abuse its power.
Second thing is, there is no real way to determine how many currencies/tokens are consumers ok with, other than to really try it out in the market. Let me use an example.
Today if you have Amazon prime TV, then they have a whole section subscriptions for channels where you can subscribe to Prime, Netflix, Hulu, Crackle, CBS, Showtime, Scifi, History Channel etc, services. Initially it started out with just Prime, Netflix, and Hulu, but now there are so many options, you can't just watch Homeland if you have these three subscriptions. The problem isn't just that you need to pay more, but rather that you have to subscribe to so many services.
This is too confusing, but this also means that this is a problem to be solved. In future (and I think some company has already started) to build a package subscription. Maybe another solution would be to have every show a pay-per-view basis (which Amazon already does).
The idea is, that the reason why different subscription services exists because of some other, unavoidable business reason. But this can be solved from the user experience point of view differently without resorting to a govt monopoly on entertainment.
Same thing goes with these cryptocurrencies. They exist for different, unavoidable business reason, but it is also annoying to have to deal with different currencies, so I believe in future there will be more basket of currencies solution (like ICONOMI) which allows people to hold 2-3 cryptos at max, and from their POV, the conversion and payment to the native currency happens seamlessly.