>>56817297Here's a chart I made to demonstrate. The impacts of IVs, EVs, and base stats scale with level. Competetive battles are at level 50, so this is what matters to most people. At this level a perfect IV (31) gives about 15 points to a stat compared to having an IV of zero. Meanwhile, EV training for full investment gives about 22 points in that stat. Natures are applied after everything else, giving or taking 10% from the total, and thus matter more when it's already a big difference.
In the chart, I used Lucario's base special attack stat of 115. In green, you can see that at level 50, with full EV investment, and a beneficial nature (like Modest), Lucario would have a 183. In red, with a zero IV score, no EV training, and a deleterious nature (like Adamant), Lucario would have 108 special attack at level 50. This means you can get a whopping 75 point difference in this scenario, translating to quite a difference in damage output. In yellow, you can see an example of a beneficial nature with a 31 IV score yielding 148. This is still 40 points higher than the worst case and 16 points higher than the best we can do with a zero IV and beneficial nature.
In-game, it's likely only to matter in places like the Battle Tower where you'll face lots of foes that with max IVs, EVs, and useful natures. In most case though, in-game foes have pretty poor values, with exceptions being Elite 4 trainers and the like. Plus, you can see how much more a level 100 pokemon benefits from base stats and the like versus a level 50 one. If you have a higher level, the advantage is seriously substantial.
