Speed of light delay could be critical in space battles, especially when you consider that it goes both ways (sensor readings -> brain : decision making -> control signal). The real question is how smart you can make computers, if you can't make them as smart as a human then you need to have a meat-brain somewhere in the middle of the battle. If you can make them that smart then that opens up a whole host of questions on sentience and ethics.

Edit: Keep in mind that your manned "ship" might still be thousands or millions of kilometers away from the enemy and controlling a vast array of computerized drones. But when weapons are zipping around at 10s, 100s, or even 1000s of km/s the scope of the battlefield changes dramatically. You can be remotely operating missiles that are farther away than the moon is from the Earth and still be in the thick of it.

I don't know if as smart as would be valuable against as low powered as. A computer would make decisions instantly, take much less resources, would die less easily, wouldn't get bored, wouldn't forget it's mission, would feel no sympathy, could travel farther, could stay in operation longer, could tactically self destruct without hesitation, would take no salary.

But that being said, I honestly can't think of a reason to ever have a space battle. You either want to blow up a planet or not. If so, you do it from an large distance with a humongous rock. If not, you land on the planet, or fly around their atmosphere and kill them the old fashioned way.

Maybe defensively you chase down an attacker to prevent future attacks? But then all you have is guided missiles and the speed of their ships. Not really a battle.

What I guess I'm saying is I can't ever see there being an attack position other than lets wait until there are no rocks in-between us and them.

We already have nuclear weapons on Earth, yet wars still happen. Space is big, incredibly so. And once there are people and industrial infrastructure sprinkled throughout it armed conflicts will probably be inevitable.

>Why would space war ships be manned when we're already flying unmanned vehicles on earth

Because the longest distance on Earth is only about 0.07 light-seconds.

And why do you think they would be remote controlled?

If you put a smart enough brain inside it, you could just upload a copy of the crew (assuming you can digitize and run human minds, of course, something that seems easier than interstellar travel). This way, the ship would not be limited by its crew. The crews responses would also only be limited by available processing speed. And, instead of lifeboats, you could transmit the crew states. In fact, you could do that regularly across the fleet for synchronization and backup purposes.

And, from the inside, it could look exactly like a Constitution class federation starship. People younger than me would prefer a Galaxy class. I, myself, am in doubt between the Constitution and the Heart of Gold. Or a big bridge like the original Battlestar Galactica. The computer could easily generate a lot of red-shirts for added drama during battles.

"Unmanned" can mean many things, but considering the OP's quote "when we're already flying unmanned vehicles on earth", he clearly meant remote control.

I meant something like a combo of AI with orders beamed every now and then.