Instant = insecure. Period.
Bitcoin security level is basically overkill. Who need to "figh" a fucking goverment and waste half a billion $ yearly on electricity just to feel "secure"? Only retards do. Government can just seise domains and close github repository, and no coin will ever appear on http website. Luckily, no government EVER attached bitcoin, ebil gobernments simply don't care.
Instant transactions is a big improvement for people who actually use coins to buy goods, not "investing" in delusion of being "wealthy elite" for buyng crap from the bottom of the food chain, and these transactions provide good enough security by masternodes or witnesses or lightning network.