what is the use of paper money in electronic world?

Paper money was there, it is still now present and I firmly believe it will remain as long as civilization persists. Electronic world may reduce its use but will never be able to abolish it completely.

hm.. nothin much just what we inherit in the barter system :)

While some people are willing to go totally electronic, there will always be those (especially older people) who will want to continue things the way they always have been. Of course, once those folks die off that might change. Personally, I don't like having a lot of cash around. It is too tempting and it is very easy to lose it. If everything were electronic, you could have problems if the power went off or something similar.

I still think paper money will be around so you can make a deal on the spot and yes do some under the table jobs. But until we have mobile devices that we can swipe our cards and make private payments then we will still have paper money just for that purpose.