This is where recognising a distinction between investing and speculating comes in handy. It's quite possible to speculate in dogecoin (relying on greater fools coming after) in the short term and make some money. In the long term it is extremely unlikely to have any value at all, so if you take investment to be long term search for value, the answer to should I invest is no.

The interesting thing about fiat (all our currencies at this point, including crypto ones, unless you want to quibble over semantics), is that it depends on confidence for its value. Without confidence it is worth nothing (Assignats, Zimbabwean dollars etc). This realisation doesn't give me great confidence in Bitcoin or any of its spin-offs though. It's an interesting experiment and noteworthy, but I think fatally flawed as a currency or an investment because of the explicit rejection of verified identity, regulation, and inflation and its attempts to emulate paper cash.

Perhaps the next currency to emerge will be corporate sponsored rather than state-sponsored, as corporations are still rising in power over states, but it will be a very interesting century, because most of the national currencies probably won't survive it, and by 2100, no-one will be using physical tokens for payments (cash). States will naturally resist any encroachment on their power over currency and taxation, which up to now has been absolute. I expect any stateless currencies which do manage to rival say the USD to come under heavy pressure from both speculators like Soros, and currency blocs who perceive a threat to their monopoly on trade.