I have a smartphone but don't know where when, how or why they were made!! I do know how much they cost.  You will have to tell me the rest.
I don't know actually why they were made, but one of the reasons was likely that they are usually pocket-sized and not as bulky to carry around like a tablet
Right you are, but LOL. I had a flip phone before i got this smartphone and it was much better. Just flip it closed and it fit in my pocket.  Most pants have a right side pocket that has a flip phone pocket inside of it at the bottom.  Useless now!!
A cool thing one can do with a smart phone is use it to pay at a store - it's called Mobile Payment, and is pretty common these days on smartphones!
Yes. McDonalds uses it and i like it.  I am trying to get the stores i shop at to use Amazon pay so that i can pay with my phone, but there is some resistance on their part.  I guess it is because of the extra steps involved, and they are already dealing with many forms of payment.  Bitcoin will never make it big!!
In the meantime you could use your smartphone to take pictures with its camera, or surf using its web browser - those apps usually come pre-installed