Simply because to do IoT there would be more coins than there is storage space available to store them. Even if there was the transaction load when people have to send all their collected pico-safecoins in payment for something.
Its is simply transaction and storage space requirements. It might be ok for 2^36 or even 2^40 coins, but after that its not practical especially in the shorter term. And then with 2^36 or 2^40 how would you get micro or pico-safecoins for IoT
Mind you the 1KB is probably the overhead needed when storing a MD and then the coin info is on top.
But as you say in your edit, it is a lot.
- For micro-safecoin (10^-6) that figure is now 421 PB
- For nano-safecoin (10^-9) that figure is now 421000 PB
- For pico-safecoin (10^-12) that figure is now 421000000 PB
- For what division using balance method (10^-18 of a safecoin) its 421000000000000 PB