There is an obvious consumer benefit. Drop off rates for games are extremely high, if this can help keep a customer engaged through a challenging or confusing part of the game then its good for everyone
Its also extremely low maintenance to record somebody playing the game and uploading it, compared to actual game development. You act like developers don't play through their games hundreds or thousands of times already. There's also no mandate to go upload 180 videos like Demons Souls. Devs can easily identify challenging parts of the game from play testing and just focus on that for video help
It's incredibly unlikely they'd expect devs and QA to have to worry about recording these videos during their normal playtesting, and most of that is spent on an unfinished version of a game anyways and things can change.
I imagine Sony has some good tooling for this, but the effort would probably be paying someone specifically to play through your game and record these videos. The cost would be based on how big your game is and how extensive you wanted the help to be.. how much time you spent vetting videos or editing them, etc... and really the cost is dependent on Sony's tooling and what it takes to get this work done.
Compared to other aspects of game dev it's definitely small.. and if Sony's tooling is good it could be really easy... we'll have to wait and see how 3rd parties use it though as it is still "Extra budget."