Unless an Altcoin is created to accommodate an extended power outage then none of these coins can be considered an improvement over Bitcoin.

If it is not an improvement over Bitcoin then it is not innovative.
Having Bitcoin and every Altcoin reliant on Electricity and an always on Internet connection is a design flaw.
Eventually we will have a major extended power loss and loss of the internet.
When this happens your coins are worthless.

It is not a matter of if ..it is WHEN !

I have been warning you all of this since 2013 lots.
Fix your shit guys.

Promissory notes are a common financial instrument in many jurisdictions, employed principally for short time financing of companies. Often, the seller or provider of a service is not paid upfront by the buyer (usually, another company), but within a period of time, the length of which has been agreed upon by both the seller and the buyer. The reasons for this may vary; historically, many companies used to balance their books and execute payments and debts at the end of each week or tax month; any product bought before that time would be paid only then. Depending on the jurisdiction, this deferred payment period can be regulated by law; in countries like France, Italy or Spain, it usually ranges between 30 and 90 days after the purchase