i saw that video the other day. very interesting stuff. it's obviously extremely concerning for west africa but i'm not sure there's much for us to be concerned about unless we have loved ones in the sahel or a reason to have to travel there. i would classify these groups more as bandits and raiders rather than global terrorists. we aren't hearing any of the anti-west, anti-israel rhetoric that was basically the whole reason for arabian al-qaeda's existence, and i really doubt the "isis" groups really have any intention to set up a functioning islamic caliphate.
this area of the world is completely ungoverned and currently ungovernable, like the video mentions. bandits and warlords have always stepped into these power vacuums throughout history. i think this is generally what's happening here and the various groups are just choosing sides, declaring which other groups are their allies and enemies, and trying to gain recruits by attaching a well-known brand to themselves. this is probably not all that different from the 70s and 80s where every third-world insurgency or warlord's army declared themselves "communist" or "democratic" in order to broadcast their general ideology and claim legitimacy.
we (by "we" i mean "civilized society", not necessarily "the west" or america) should keep the pressure on these groups, and indeed all banditry and barbarism wherever it arises, but just because these guys say they're "isis" we shouldn't worry that a group from the back woods of burkina faso is plotting to bomb london.