Bitcoin is an exceptionally poor currency. It's expensive, it's slow, it doesn't scale... Nothing in the OP post supports the subject of the thread that bitcoin could win the currency war. Bitcoin will have to solve all three of it's major problems to win any type of currency war. Cash is superior in every aspect right now, and centralized payment systems are far superior to a decentralized blockchain system thus far.
All this points of yours really needs debate, saying that centralized currency is far preferable than decentralized currency, i think these really need more explanation or insights, it's accepted that centralized currency come into existence before digital currency, which digital can be decentralized currency, because looking at the current situation of nature it's obvious that people uses the digital system of payment which might be cryptocurrency and especially Bitcoin, so it's left to individual to decide for a means of payment, so am disputing the fact that fiat currency is superior than crypto, automatically it depends on the environment we found ourselves for transportation, many people currently accepts crypto because they use it for investment within short period.
Well, point of clarification- I said
centralized payment systems are better than bitcoin, and then second point is that because of bitcoin's inherent flaws, cash is a better type of currency. An example of a centralized payment system is Visa or Square. The payments are instantaneous, cheap and trustworthy. Compare this to bitcoin where payments are slow, expensive and trustworthy. Visa and Square are hands down better payment systems than bitcoin, it's not even a fair competition because bitcoin is so slow and so expensive.
As for my second point, because of how slow and expensive bitcoin is as a currency, cash is far superior to it. Cash holds a steady value and is far easier to use. Digital payment systems make up the one shortcoming cash has compared to bitcoin in not being able to be used online.
So those are my two points- 1) centralized payment systems are faster and cheaper than bitcoin, and 2) centralized payment systems make cash a far better medium for exchange.
Don't forget that centralized payment systems have someone to go to if something goes wrong. Also, if you mess up the sending or receiving address in a defi transaction, or put in the wrong gas amount even, the entire payment could be subject to being lost.