I got my att, str, def and HP skill to lvl 99 before the skill capes were released. Obviously, you hit harder at lvl 99 (and with super pots) than you would at lvl 96, 97 or 98. That was my main reason for getting them to 99. I don't believe getting level 99s in fishing, woodcutting, cooking, fletching, crafting, etc would makes a big difference when doing these skills as compared to having level 96, 97 or 98.