If you know what breaks the system, its very easy to avoid it and tailor the experience of playing the game to your wishes. There is 1 good argument for optimization in this game however, it is very good at telling you what to avoid if you want to have a fun experience. Here is a guy beating the final boss using the cat summon for example. Optimization does not matter in the game, you can beat it doing pretty much anything if you have the time, patience and creativity. Basically, if optimization mattered in this game, then the game would skew heavily towards physical damage. There is also the weird caveat that buffs multiply with physical damage but add with magical damage (who knows why), which also further skews things.

In theory it would also have been possible to offset it by giving magical abilities much higher multipliers, but for the most part, this is also not the case. This is not the case however and enemies both have high elemental resistances and usually have higher magical armor than physical armor. For that to be true, there would need to be some enemies which either have high physical resistance, or a high physical armor but low magical armor, or a combination of both.

In theory such a system is capable of encouraging having a party which is more generalized, provided that in some situations you would want elemental damage over physical. Click to expand.The whole discussion was about whether the armor system encourages sticking to a single damage type or generalizing.

Divinity original sin improve armor