Well you should care if you genuinely think they are overvalued, because that means if you are genuinely investing for the long-term rather than trading, you should probably wait for better opportunities before buying more (unless you think the market will never realize the real value).
I have my doubts on how useful cryptocurrencies will ultimately become. It's likely they are niche in their use for a long time because of the many obstacles they face, ranging from awareness to understanding to the budgets that alternative solutions have available to them. Don't think the banks are sleeping on this, or any of the other large enterprises.
In other words, the real "utility" of cryptocurrencies, especially ones that aim to be just money, will likely be far lower than what people project for the foreseeable future of at least 10 - 20 years (although I hope to be wrong on that).
You ignore the fact that many cryptos are not aiming to be digital money but aiming to solve real world problems. Look at Medichain or use the use of Ethereum in Brazil to cut across ballot rigging.
Those who disparage cryptos ignore the fact that our current fiat money system is not exactly working very well is it? The last 10 years have seen a gigantic transfer of wealth to the 1%.
I don't want to spend my crypto. I want to use it for real world uses. I recently bought some gold with my crypto as a hedge against the dollar crashing and the possibility of hyper inflation thanks to the trillions printed by world central banks to pump up paper assets.
Most of the people commenting here lack a historical perspective and probably have never done any research on economics. Read Jim Rickards book, The Road To Ruin for a good overview of the giant ponzi scheme created by world central banks or the Bubble and Beyond by Professor Michael Hudson.
I don‘t think that crypto will ever replace fiat completly. Imho they will ecome an alternative to fiat. Especially in countries like Venezuela and Simbabwe, where the national fiat is more unstable like the cryptos.
I’ve been following BTC since 2010 with almost complete skepticism. Nonetheless, its value has obviously defied my beliefs. Luckily I invested in despite my reservations. It continues to surprise.