largely disagree .. yes is not effective in some games, but it is in many others . and is one of the reason why some get shocking results facing weaker teams
i did a season without and a season with bonus, got double the number of goals
Set the bonusses at your level (update every season) will result, when win a match, in a small improve of your players morale.
And better morale, better performance.....
So yes, it's effective