I want to get some krk rokit rp5 g2 speakers.
Yes, good speakers are worthless without an amp, however, these are powered speakers, and do not require another amp.
Those speakers have a built in 70 watt amp. Just about all computer speakers do since that 1/10th of a watt you get out the jack isn't going to power anything bigger than headphones. But, those speakers are really overpriced. You could get better sound for less than half the money.