Yeah you are right but it's just how they did it in here.
They gave people 15 days to exchange the bank notes for smaller ones or deposit their old notes in the banks or exchange for new ones, we can all agree that this looks like a really small period of time but due to the nature of our economy it's actually a decent time. But the bill is not really "banned" it will be tho and I will explain you the reasons a bit later.
In my case, I deposited all my 100 notes without any problems by monday. I just use debit/credit cards now and other small notes to make cheap purchases.
It's incredible hard to find actual correct information on whats going on because all the media is focused in creating chaos and missinformation, this is an actual good source where you can see the explanation of why only the 100 notes are being replaced on this 1st phase
http://www.analitica.com/economia/canje-de-billetes-en-banca...
But an small resume is that only the 100 VEF notes are being replaced now because they represent the biggest percent over all the notes (is around 50%) so people will want to have a bill of 20.000 instead of 200 bills of 100 VEF.
Once the 500, 1.000, 5.000, 10.000, 20.000 notes are around, they will finish replacing the other small notes 10, 20, 50 and 100 leftovers for coins.
But well, as I said before, the media has started a campaing to make people belive that right now their money will have no value at all and a bunch of other lies, this of course leads to desperation and to problems like we had today where there was violence at diferent banks around the country.
And to explain why the bill will be banned after 15 days is pretty simple, the money in this country has a super high rotation, bills NEVER sit in your pocket or your wallet for more than 1 hour, aditional to this, money in cash is barely used now, a huge percent of the transactions are made electronically because is just not confortable to have a pack of 300 bills to buy food for 3-4 days so cash is actually not really used because of high inflation
So yeah if after 15 days you still have bill leftover you pretty much were into corruption, drugs, money laundering, smuggling, etc and thats exactly what the gov wants to avoid, to all those guys who spend years smuggling in the borders and have containers or warehouses full of 100 VEF notes.
Take a look of this video: https://www.youtube.com/watch?v=p23Fn1LVGv0
This is an asian guy (well known to have smugglings business) showing how many 100 VEF bills he had, it's just hillarious.