Even if BTC only went to 100k.. haha.. it would still require sub-satoshi payments if you were counting every light switch on\off, or every single byte of data sent from a certain server.

Nobody's going to be counting that kind of IoT stuff on the blockchain, there just isn't enough space (bytes are too valuable).

... Lightning network.. will allow near-infinite off chain txns. Your light switch, along with the rest of your house, will have a payment channel open. ping ping ping. Of course they won't be on-chain txns.

It's really bad bad very bad idea!

Only integer numbers.

Not to worry, Bitcoin is never going to use floating-point arithmetic because rounding errors would screw up the total number of Bitcoins over time - cumulative error grows exponentially with number of operations. Integer-math guarantees that the number of satoshis in circulation will always balance correctly.

I'm not saying use floating point.. I was just using that as an example of doubling precision from float to double.

I'm saying increase the number of ZEROs allowed after the decimal point, whatever the number format. so 0.0000000000000001 would be a valid amount. There are still only only 21 million btc.