It's a great idea but it's not portable in other simple vim modes that generally lack the possibility of such a configuration, and if they do provide it, now you have another configuration to take care of.
Why I like my solution :
It takes three seconds to activate in any OS and it's available system-wide
I've seen a lot of people recommend jj, but that's part of something I type a lot, so I had to choose another. jk works okay too, because I don't use that acronym.
:)