Mag is obviously stronger than str.

[onget]

flame orb:fire 25SP,55power,range3 3*3 area cannot miss ignite
earth break:impact 30SP,55power,range1,3*3 burst cannot miss
Why is earth break too weak compared to flame orb?
There are plenty of such obviously inferior physical abilities.

Magic is also excellent in element. Physical has only 3 elements. Magic has 7 elements+healing.
Magic attacks can easily weak point attacks,And easily avoid resistance.
And although there are few physical weaknesses, there are many magic weaknesses.
There are also a lot of magical resistance, but that is not much of a problem.

[Ferret]

AE physical attacks qualify for physical passives like Venomous, Numbing, Nightbringer, etc., which still work at full effect on them: this is why physical-based AEs are usually more expensive than their counterparts in Magic. Magic passives tend to have effects that don't necessary become that much stronger just because you're hitting multiple targets.

Physical types also tend to have much, much better cross-element compatibility than magical types. Slash, Impact, and Pierce pretty much don't discriminate in terms of how passives that benefit them work: things like Parry, Venomous, Bloodlust, etc. work on all of them. This is different from how the magic elements work: in most cases, magic passives tend to be specific to a single element: getting the most out of one element requires dedicating multiple ability slots to that element... which increases your risk when you run into something that element doesn't work so well on.

It's certainly viable to build multi-element magic builds that give up on focusing on an element to be able to hit multiple elements easily so that resistances aren't an issue: but a physical build gets to do this *and* still have lots of passives that boost their abilities.

Finally, it's also worth remembering you get a defense bonus based on your Strength stat, equal to 1/2 the bonus value. Magic doesn't give any extra bonus of this sort.