SATA cables without the locking clips are very annoying. As you say, they can just fall out of the ports. ASRock motherboards are often bundled with them, which I suppose is because they are cheaper and it keeps the price down for budget buyers. Luckily all of the Asus motherboards I've bought in recent years have come with a load of good quality SATA cables that seem to plug in very securely and work well. I'm always impressed by how much Asus normally bundled with their higher end boards.