I hate when noob players forget smite and keep trying to jungle because in their head they think if we don't have a jungler then we are gonna lose. People who think like that are the biggest reason they lose. Here's why.
If you went dual top and because someone forgot smite so you and the other person are behind on exp or gold, and then you decide to start jungling around level 3 or up, you basically came and messed up the lane for your top laner as soon as you go jungle. When you go jungle at that point, it is beyond stupid because not only will you be suffering trying to farm jungle without smite either dying or having very slow clear and sustain, but your teammate up top is now getting his ass handed to him because now he is a level or two behind with some gold behind if you took all or some of the minions. So at that point, you should just stay top or at least go mid and bot and do some ganks to put some pressure and damage onto other lanes.
The other scenario is no one takes jungle for whatever reason and the guy who thinks "we need a jungler or we will lose" so they decide to jungle without smite and they are basically useless all game because they provide zero ganks, are behind by 2-4 levels compared to anyone else on the team, and struggling to farm jungle camps because they don't have smite. So then all they do is leech exp and gold from other lanes when the other laners get ganked by the enemy jungler.
Jungling is important or highly effective, i agree with this. But jungling without smite is purely stupid and basically inting.