For sure 100% people are still gonna be using it though in smaller scale. It's undeniable that majority of usage is always for investment though bitcoin is also good for payment.
If government somehow out of the blue announce to outlaw BTC, people will sell it and price plummets, but guess what, it won't be completely dead, I'd even say it's still gonna be frequently used, the blockchain would still have many transactions.
The biggest downside is just the price going down. But that's about it, we're used to bitcoin at sub 1k anyway. However, there's really slim chance bitcoin gonna be outlawed.
But is it really worth the risk? I mean, most people would be afraid of getting caught by the government. They could either face fines, jail time, or worse-case scenario, death. With market prices going all the way down the drain in an instant, almost no one would use BTC or altcoins. It's has always been about the money.
Why would it not be? People take stupid risks for all sorts of useless or even personally damaging behavior. Bitcoin is freedom and nothing comes even close to it. How much would you risk for freedom if not everything?
My guess is that once crypto is "banned" worldwide, BTC will lose investor appeal as a store of value. It will become a digital currency alternative to Fiat. Just like how Satoshi wanted Bitcoin to be used in the first place. At least, most governments are supporting crypto. So an outright "blanket ban" would only be a concern in the distant future. Just buy, "hodl", and forget about the rest.
This scenario is extremely unlikely because there are already too many big players involved. They won't let the government make them lose a lot of profit. Incentives are on Bitcoin's side.
Come to think that Bitcoin or crypto as a whole did become that popular just because it do totally oppose decentralization and if ever that becomes outlawed then it do really serves its purpose not unless or excluding into those projects or coins which are totally centralized then it would be that excluded. Do people do continue to make use of it? Of course it would be and because of decentralized aspect or benefit then we do have that freedom and since its mostly anonymous then there's no way that government could easily tracked it out.
Will people be continuing on using it? It will be that a matter of choice and if you are someone who dont want to put yourself into trouble but if you do know on how to go avoid with those potential getting caught up then you would definitely be doing it. We do know on how good and profitable on investing into crypto is on just simply holding up your position or holding up your coin for long term then it will be giving out that kind of opportunity but of course it will be basing up into the coin/token that you are holding because not all project will be successful. Each country does have that different laws and regulations when it comes to crypto but if we do base up on their differences comparing wayback into those previous years then we are that at least having that good rate or condition basing up on the acceptance and recognition of crypto specially with Bitcoin. It might not that fully being adopted but we are seeing it out that it is gradually heading into this situation on which we can definitely say that we are heading towards global adoption on which this do sounds a very positive thing for crypto enthusiast. Somehow there are those places in the world on which that still not prepare or being ready on having that acceptance about crypto just because they will be always that skeptical of it because of being decentralized and anonymous on which this has always been the issue. Usage by people will definitely be basing up if they do saw that they can be able to make up some transactions without getting caught. Actually it is that very risky because government is your enemy on here and we do know that on how hard that going against about government policies and laws on which once get caught then your fucked up.