There are many things that don't appear at Grassroots level (such as decent ARs lol), but I can see your point. Personally though, I do think it should be used at the higher levels of the game, FIFA tournaments, UEFA, and top domestic leagues (Premier League) at the very least.
Whether we like it or not, I do think the involvement of technology is inevitable, and I would hate to see the game stopped regularly to refer to a 'video ref' BUT, I do think it could be workable without adding too much time to the match.
My idea has been lifted from Gridiron - give the Manager of each team coloured flags. Let's say they have one per half. An incident occurs on the FOP, the manager thinks the ref got it wrong so throws the flag. Ref stops game. Video Ref then has 60 secs to review the incident and communicate decision to Ref on Field.
If he upholds the ref decision, then play restarted with IDFK against team that called for video.
If he disagrees, then play restarted with the correct restart for the incident, as it occured.
If he can't reach definate decision, then continue with IDFK as above.
Now, if you limit the number of flags a manager can use per half, you also limit the hold-ups in the game. Say they have two flags per game, but can only use one in each half. If not used in 1st half, CANNOT be carried into 2nd Half.
Game is only stopped for ONE MINUTE for each flag, therefore, only ever adding 4 minutes maximum to the total game. 2mins at end of each half.
So, the manager has to decide whether to use the flag or not, so a snap decision 'Is it worth it?'.
Those bosses that question the ref all the time, especially post-match, the question is put back on them : 'You could have flagged it'.
The TV coverage would provide the feed for the video ref, and it could be implemented at very little cost at all games that are covered by TV cameras.
Could also be implemented to Grass Roots level, although 'a bloke with an i-phone' may not catch all the action