Spear vs Knights... am I missing something?

[Kromm]

Originally Posted by sir_pudding

Sure, he could be a knight, but I suspect the OP was using "knight" as a shorthand for "armored fighter".

Well, what the OP really wanted to know was whether there's any reason to buy anything but combat skill. It's just that we all jumped on the example instead. Of course, examples with zero context make it difficult to answer questions authoritatively:

"In a free-for-all point-spending contest without any commentary on genre, realism, or campaign world, is there any reason to buy anything but combat skill for a gladiatorial pit match against other humans at melee range?" No.

"In a free-for-all point-spending contest without any commentary on genre, realism, or campaign world, is there any reason to buy anything but combat skill for an adventurer?" Yes, because you still need to search, sneak, talk, travel, etc.

"In a moderately realistic campaign world based vaguely on medieval Europe, is there any reason to buy anything but combat skill?" Yes, because you'll be limited to skill 12-14, maybe 16 if you're a master, and need to eat, speak, travel, earn your keep, etc.

"In a fantasy campaign where 'knight' just means 'heavy fighter,' is there any reason to buy anything but combat skill if you'll have a party to back you up at everything else adventurers do?" It's your call, but remember that many monsters don't care about being hit and have no vulnerabilities . . . and some always strike from surprise. Do you feel lucky betting on eye-pokes and parries, and never being grappled from behind?

"In a campaign about Senate oversight committees, is there any reason to buy anything but combat skill?" Yes, because you'll never use combat skill (or if you do, you'll be shot by security).

. . . etc.

The toolkit nature of GURPS absolutely requires that all queries of this kind specify power level, tech level, realism level, genre, campaign focus, etc. Asked in a vacuum, the answer is always "maybe."