Scaling is something developers care about, but in the nascent field of cryptocurrencies there probably no single solution.
It should be noted that with your credit card example, however, that credit card networks charge a percentage of the funds transferred while in the case of Bitcoin it is instead a fixed fee. Should you instead have said that it costs $5 to send $5000 it would have been equally true but sounded quite different.
That Bitcoin as it is described in the whitepaper doesn't scale to even a single US credit card network should be obvious to any reasonably informed reader. That every participant in the network store everyone else's transactions forever has its limitations. Does that mean the technology is useless? No, it means the use case is different from credit cards.
It seems possible to build payment systems on top of Bitcoin that fills those use cases, and sidechains and payment channels are research along those lines. But just as crypocurrencies were a theoretical possibility twenty years ago, one should not expect working products too soon. It's not like there is a shortage of payment solutions in the meantime. For end users, credit cards offer a negative cost, so even then we should not expect the use cases to be identical.
Not that this is a whole lot better, but the cost is $1.48 for fastest confirmation time, and $0.42 if a delay of 15-300 minutes is acceptable to you.
Source: https://bitcoinfees.21.co/
Paypal transactions, Swish (Sweden), etc. etc. are instant and often with zero fees.
* Fee is not dependent on amount of money you're sending. You can send $200M worth of Bitcoin to a company in China and it will only cost you $1.50, try doing that with a wire transfer.
* Transactions are "final": after 3-6 confirmations you can have a great degree of confidence it won't get reversed
* Compared to Western Union or MoneyGram, it's still faster and cheaper
But in its current state, bitcoin is definitely not a replacement for your Visa card when buying groceries at the store. Maybe Lightning will change that though.
2. So, if transactions cannot be reversed, and I erroneously send money, or am tricked into sending money, I can't get it back?
3. So, BitCoin wins only when compared to Western Union and MoneyGram. Oh, what an achievement.
In it's current state bitcoin isn't a replacement for anything, really
Scalability has improved somewhat during the past two years and most developers believe it is time to increase capacity as well. The question you refer to is how to increase capacity, within the scaling constraints.
I understand the ambition to be neutral in a contentious issue but one must be careful as not to spread misinformation. "Discarding less useful data" is not how segwit works at all. Segwit does away with the fixed blocksize and uses instead a flexible block size of up to four times the previous fixed limit.
The discarding you refer to is the backwards compatible aspect of segwit where it can communicate with older nodes that do not implement this feature by not sending them the data. It is not discarded and a supermajority of the network must use the full larger blocks in order for this to be secure. It is merely a transition method to allow for upgraded and non-upgraded nodes to briefly share the same network.
So what you refer to are two methods for larger blocks. One must be upgraded with a flag day where everyone upgrades or you lose money, and one allows for a transition with a certain amount of backwards compatibility.
It is also misleading to describe this as two "sides". The sides are mostly within social media. The technical debate has been had and there was overwhelming consensus among the developers that the backwards compatible way should be deployed first.
If the technology takes off and solutions such as Lightning prove viable, most developers agree that the non-witness part of the blocks probably needs to be upgraded as well.