Voadam
Legend
A wizard who dump stats strength can rely upon others in the party to handle any strength checks so there is no significant negative impact on the PC for giving themself the dump stat either.But, let's say you're playing an INT 8 PC. Now, because of how smart you are you routinely take charge, plan assaults/tactics, etc., things that repeatedly would be difficult for someone of average intelligence, let alone lower intelligence. What you are doing is giving yourself a dump stat where (due to other choices you make) really has no significant negative impact on your PC. Because you play your PC smarter than they really are, role-playing-wise you have all the benefits of a high INT PC without the high INT.
I have seen this sort of thing often enough after playing for over 40 years. Fighters with INT 6-8 come up with brilliant tactics, solve complex puzzles, etc. because the players are brilliant. Then, to offset the INT penalty (in 5E), they rely on other PCs to make the Intelligence checks with their bonuses and even take Resilience for INT saves, or choose classes (like Rogue) with INT saves...
Both are impacted by the mechanical impacts of their dump stat to the same degree.
The physical stats usually have zero constraints on roleplaying and so are strictly mechanical restraints.
The question is whether the mental/social stats should be similar in being strictly mechanical restraints or should be roleplaying restraints as well.
If you go with roleplay restrictions as well this means that class builds that favor physical MAD have a choice of playing roleplay concepts that either fit low mental/social stats or shift stats to match the roleplay narrative concept but are subpar builds for the class.
If you wish to roleplay smart, be a wizard or a sub-par high int anything else.
A smart leader narrative role like Hannibal from the A-team or Roy from Order of the Stick have the choice of being behind the curve on stats fighters or play wizards and have no stat power drop.