IVs can give a maximum of +31 points in a stat at level 100, so arguably they are quite important, yes! If you're playing competitively then chances are all of your opponent's Pokémon will have max IVs, which for stats like Attack and Defence won't make a huge difference in the grand scheme of things, but the difference between 0 and 31 Speed can be game changing, especially in a meta full of such powerful sweepers. IVs aren't important for in-game teams, but for competitive teams they can occasionally win or lose you the match, especially if you come up against the same Pokémon as you're using but with higher IVs, so I'd always aim to get them as high as possible. EVs and base stats are more important to focus on, but IVs can be a big deal too, especially in the lower base stats where +31 could be a huge amount to add.
And, as said above, IVs are also used to determine the type/power of Hidden Power, so they're worth looking out for in that regard too.