2. confirmation speed as above posted mentioned is determined by the time between blocks. and that time is a somewhat fixed time. bitcoin is designed in a way to have 2016 blocks every 2 weeks which translates to 1 block every 10 minutes. this doesn't change with more or less miners. when the number of miners (or more accurately the hashing power) changes there is thing thing called "difficulty" that changes so that we get the same 2016 blocks every 2 weeks again.
Imagine the queues in the shops if Visa batched their transactions up and authorised your payments in 10 mins blocks. That is probably the main reason Btc hasn't (and probably wont) taken off. People just don't want to wait. Even if they halved it and halved it again, that would still be 2.5 mins waiting for payment to clear. The lightning Network is ok but if your main selling point is something that just bypasses the main protocol, then why bother with the main protocol.
well if you want to compare then at least do it honestly.
first of all Visa is not money, it is credit or better said IOUs.
secondly it takes for a merchant up to 3 days to receive a payment that was done through Visa network. so in comparison bitcoin takes 432 times less time to confirm. so Visa has to half, then half,... until it reaches bitcoin speed.
third when you pay with bitcoin and it is confirmed then you can no longer "charge back" but all the other payment systems have this charge back option so the merchants are always in danger of fraud and it does happen every day.
forth just because you think bitcoin won't take off doesn't mean it hasn't already happened. there are millions of merchants that are accepting bitcoin. from small shops selling crap on the internet to big corporate like Microsoft.
and finally using lightning network is not "bypassing" anything. it is a
layer on top of the main protocol.