IIRC, it is a political attempt to keep work locations within AL, rather than a neighboring state. Maybe the first attempt to directly reward for not having out of state remote workers. (And not that different than how GA, for instance, rewards with tax breaks for TV type productions - why so many things are filmed in GA.)
I would not call it strange in the payroll world. All seems to be fair game at present (anything goes). Wayfair ruling has emboldened states to cross their borders to gain income, so now a state is at least temporarily rewarding for staying within their borders. With the rise of many min wage to more than double the federal number, employers are wisely looking at lower min wage states to have employees performing services, especially if there is low or no company income tax nexus caused by the remote worker.