Attributes are not the only method to discern a character's physical attributes.
Do you go up to someone in real life and ask, "What's your strength attribute?" The answer is no. We can tell, with a fairly high degree of accuracy who is stronger between http://api.ning.com/files/xhixLk1YGG7-ZAqE5*qfWYkQwR8gT33J80urKIDWie92q99rfNJY9cuWQwBc0SgJL8R62nd61y4-emKIBt2FHbI8WyqhJXAp/gandhii.jpg and http://static9.depositphotos.com/1003940/1113/i/950/depositphotos_11134190-Full-body-of-muscular-man-exercising-with-dumbbell-on-white.jpg, just by looking at them. Same again for runners, you can typically tell whether someone runs or walks (ALOT in the case of walking) by looking at their calf and hamstring muscles. Obviously it isn't necessarily a 100% thing, but for most cases, I'd suggest you can tell by cursory glance.
How does that translate to mental stats? Well, that's a somewhat difficult one to broach, but thankfully you limited it only to physical characteristics so I won't need to go into it (much) at all. Even in real life our attempts to measure intelligence are somewhat... hit and miss.
Charisma? In social gatherings, sit back and observe. It usually is pretty clear who is charismatic or not.
If the game is providing visual, audio or other feedback on how well we are doing things in the game, if improving or heaven forbid declining in some aspect, then we don't ever need to see attributes in the game outside of character creation. Attribute assignment as you play the game is a disconnect and not immersive.
D&D attributes are not intrinsic to roleplaying. I can't say that strongly enough.
In it's most simple form; roleplaying is playing a role.
I would take that further; roleplaying is playing the role of a character in which you act and think as they would.
Attributes are part of a system that can be used to guide a roleplay experience, but it is not the only method, nor the be all to end all. Attributes are great for pen and paper system. Let me say this again; attributes are great for pen and paper systems. But it's 2013 now. If the video game industry can't come up with a system that makes use of the tools it has that a pen and paper system doesn't, then there really isn't much hope for RPGs in the future of this nature.