If you have multiattack a net will cause advantage on your follow up attack, while also taking away an entire action from the enemy (or at least 1 attack made with disadvantage if the enemy can do slashing damage). So in terms of action economy it is pretty good if you are confident you can hit with it and the enemy does not have a slashing attack.
Where it really shines though is on a battlemaster archer as a bonus action using quick toss and sharpshooter. You don't get the quick toss damage or sharpshooter damage, but you also don't get a penalty for using it from range. It uses a bonus action, so it is not competing with your attacks. It gives you advantage on your follow up shots (as well as allies shots), there is no save against it if it hits, and it takes an entire action from the enemy. On top of that if you use it after an enemy is hexed on strength and has disadvantage on the check, there is a decent chance it will restrain him for more than one turn.
In terms of quick toss sharpshooter, what you are competing with is the 22ish points of damage you would do throwing a dart (2.5+4.5+4+10) with quick toss instead of throwing the net. To see if it is worth it you need to consider the advantage on your next two shots with your longbow.