Ok, guys. Let's start with basics. I.e. let's empasize a fact where ABSOLUTELY every currency fails now.

Try to download BTC/ETH/SHITCOIN wallet. How much time will it take to sync with network? Eternity?

Well, this should happen instantly actually, but currently it does not. Why?

My time to sync is 8 hours from a fresh wallet that I downloaded off of the internet and had to set up from scratch, disregarding any sort of additional data I may have which would speed up the process or allow for me to have the data ready to go. That is a few hundred gigs of data and isn't something normal, yet I can get it done in 8 hours.
Now look at the network infrastructure designed for credit cards, debit cards, all sorts of cards that have to communicate with some server at a location. Far more extensive and harder to set up, with a much larger time investment for the company. Why is that? It could only be 8 hours at most to beat Bitcoin.
Alternatively, for your "instant" sync, why not use a lightweight wallet? Mind answering this?