What is the purpose of Speeder ranking 2 & 3

Best thing to do is just play the game. You'll have enough creds before you know it. But some of the best ways, is to just do quests and sell everything, and also the space combat missions. But you'll also get some from PVP.

You can make over 100k a day easy just doing some dailies.

Pick up a gathering skill and sell the mats.

As has been mentioned, do the level 50 dailies on Ilum and Belsavis. You can make that 500k in one day if you include things like selling loot on the GTN and slicing lockboxes. Selling loot will probably depend on your server's population. And the speeder skills are hardly a credit sink since reduced knockback alone makes them worth it.

I think the knock-off protection is the far more valuable part of the more expensive speeders. The slight speed bonus is just a perk.

You notice the difference that extra 10% makes if you are travelling anywhere in a group with friends and someone hasnt got the rank 3 yet lol
You keep having to stop to let them catch up

You can make 200k credits per day just from the non-heroic dailies and space missions. Doing the heroic missions will net you an extra 30 or 40k credits.

Dude!

It could take a whole day or two of doing dailies to get that wopping 200 or 300k!!!111!!1!

That's an eternity for the ADD players of today who want instant gratification just for logging in, PvP artifacts just for showing up, and uber rewards for every little trivial action.

While I agree on making credits from level 40 and up is rediculously easy (Can make about 100k from space missions alone if you have an hour to spare, + dailies) I do think that spending those credits on a 10% speed increase is not worth it.

Myself, I recently got the second rank of speeder piloting and part from getting access to new vehicles, I almost can't feel the difference. Either take away speeder piloting rank 2 so that one may actually feel the speed differences between ranks, or make a larger percentual difference between them. They're called 'Speeders' for a reason, after all.

Edited.

Do like... 5 or 6 quests on Ilum?

I do agree though that speeders should be faster, and the speed boost from training should be more noticeable. IMO it should be 100% / 125% / 150%, but I'd settle for 90/110/130.

It's not that difficult to make money in this game. In fact it's probably too easy. So coming up with the scratch to get your upgraded speeder really isn't that much of a chore.