I say both are measurements on the skill of a player - as they basically measure two things - human vs AI and human vs human
I think you will agree that AI is not equal to human.
Take myself as an example - I play regent civ3 - I have 1.29 and will get conquests.
I ve only played 1 tbs game against a human this side of the millenium - and it was only half a game of SMAX.
I have good control of the AI at regent (havent had time to move up, as I am mostly preocupied with studies
)
I do not think I could have the same level of control with a human regent player though - at least not unless I paid more consideration to more advanced strategies and tactics than the ones I use now.
As many threads have pointed out - the AI is limited to use what firaxis programmed it to do - and not use reason - therefore one cannot expect single player to measure the same skills as multiplayer.
@MP being fast games: Well - that is also a way to measure a skill, just like being able to use any civ, any map type, any victory condition and any tactic - are measurements of skills.
Some games are fast, others are not
Just my 2 NOK though