Quote from: not.you on February 19, 2015, 02:35:15 AM

I had to go and read about side chains since I am unfamiliar with the concept but what immediately stands out is that if you are using an alternate block chain to accomplish for bitcoin what bitcoin cannot accomplish on its own, then why use bitcoin at all? Why not just use the side chain as the only block chain?

Different sidechains will have different use cases and it is likely they will specialize in different areas and have different security models. In the unlikely scenario that one sidechain becomes popular enough where bitcoin or other sidechains are never or rarely used bitcoin will remain secure as long as block reward can pay for security. There may have to be changes under this unlikely scenario in the future once we become more dependent upon transaction fees covering the cost of security of the main chain. There are solutions to fund this in such unusual scenario.

Quote from: not.you on February 19, 2015, 02:10:35 AM

Bitcoin suffers from block times that are too long to ever make it completely practical in a face to face situation (like in a brick and mortar store). Not impossible mind you, just not practical. And I see no way that there could ever be a consensus to change block times. It would require fundamental changes to the difficulty calculations and conceivably the total coin supply. In my opinion a digital currency with faster block times will eventually succeed where bitcoin never can due to that limitation alone.

In realty the only thing that matters is 1-2 second approvals at the slowest for in person purchases. People aren't going to wait 30 seconds, 1 min , or 2.5 minutes.

Bitcoin already has solved this problem like credit cards have with off the chain confirmations based upon risk assessment tools and looking for signs of double spending on the blockchain before the first confirmation appears with coinbase and bitpay. Anytime I buy something in person with BTC it is instant. Did you know that many cc actually take up to 60 days to confirm vs Bitcoins 10 min(People just assume that a approval is a confirmation when it isn't and can be reversed)?

In the very near future interpayment channels will speed up approval times to make them instant in a more trustless manner http://impulse.is ... and sidechains as have already been mentioned.