There is a lot to tackle in this OP.

Cryptocurrencies is a general term and while it includes Bitcoin can in
some circumstances exclude Bitcoin, depending on who is using it.

While we know the benefits of lets say Bitcoin and crypto in general
and while some countries are presently recognising it and more to
follow possibly this year, notably in Europe, Governments will not use it
because they cannot control it.

Governments will be using their own controlled cryptocurrencies but this a way
off in the future.

Altcoins have uses but it depends on what they are, the development
and how they have been adopted.

There are hundreds of alt's but a few handfulls of sucessfull ones.