But in this feature, you always frighten with your physical power, so it should be changed imo.
No, you're misunderstanding what Charisma is and what it represents, as mentioned. You are not intimidating with your physical strength - you aren't
physically doing anything to them. You are attempting to impress up on them that your physical strength is worth being frightened of - you are trying to project that you are to be feared. This is not about whether or not your strength
is something to be feared - it
IS, and that's a fact! - this is about how well you can convey and impress that on others... which is Charisma.
Think about it the other way around, and it might help:
Let us imagine a powerful character. They are a blacksmith in a township, but they are strong and capable, and when push comes to shove they have a force of prowess that is to be reckoned with; they've got 20 strength and 20 con, and they are built like a mountain... however... they are quiet, unassuming, and in truth, they are socially anxious and a little bit self conscious about their size. They grow uncomfortable if they have to talk to more than two or three people at once, and begin to lose their train of thought and fumble their words when they have to deal with that. They have a Charisma of 5.
It does not matter that this individual can literally lift a house if they have to, and it does not matter that they win every physical competition and feat of strength or ability in their township at every festival every year... they simply don't have any presence, and they lack the ability to project or impress their presence on others. The others in town are not afraid of them - and rightly so in this case - but even if they tried to be brazen and intimidating, they'd likely stumble over it, hesitate at the wrong moments, and in all likelihood, folks wouldn't really take them too seriously.
Now, you CAN walk into a university of the arcane with your 6 intelligence barbarian, and you can, in character, start having a conversation with the archmage about theoretical magic... but the other players at the table will probable side-eye you, because you're really not playing in character at all here, and it makes no sense in the world space. The DM might say you can definitely attempt this, but may say that while you feel as though you are speaking with that high level of sophistication, in reality, you're not, and the archmage is doing her best to be polite and wondering how you got in here... and when you roll, you will be rolling with your negative intelligence modifier.
Just so, and exactly the same... you CAN take your barbarian with 6 Charisma and, in character, start shouting and raving with great volume and gusto, flexing your muscles and roaring with enough fervour to make the boldest quake in their boots... But for the same reason that the players side-eye you at the university, they do so here as well, because you are not playing in character, just as you are not when you try to debate the archmage with 6 Int. You CAN attempt this... and it may even work, but when you roll, you will be rolling with your negative charisma modifier, because that is what you are using.
If you are actually using your physical strength to enact the intimidation - that is, actually physically interacting with the target to demonstrate that your strength is to be feared, then you could certainly have the grounds to roll with strength... but this ability does not do that. This ability -
Intimidating Presence - is quite literally using your
menacing presence to intimidate a foe; it is
pure Charisma, and asking to change it to strength, because-I'm-good-with-strength-so-can-I-please, is just metagame. If you want to be good at frightening people, don't dump your Charisma... and ideally... play your characters to something at least moderately in line with the scores you gave them.
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It might be worth bearing in mind - Berserker has the moderately unique ability to get that bonus action attack without needing to take the attack action. very few classes or perks have the ability to do that, at all. Frenzy berserker, however, can absolutely use their action for other things, and still take an attack every round with that bonus action... one example of which is using your intimidating presence to keep something feared while you continually harry and hack at it.
