This is only used to "tack" the mulch covering the new (grass/turf type) seedings on steeper, erodible areas on newly constructed pond dams, dry structures, borrow area slopes, etc.

Some NRCS construction projects 'here' require the use of a tacker.  

I've used it on our ground when seeding down newly repaired waterways with pretty good success barring a freak hard & heavy rain. 

Prepare your seedbed normally, seed it, and then spread the mulch with a hay processor, and 'tack' it down and make the mulch stay where you put it.

By tacking the mulch, the main problem it overcomes is preventing the mulch from being carried away by either wind or concentrated flows of water = improved seeding stands in critical areas and less rill &/or gully erosion.