I’ve cracked more than my fair share of fresh coconuts, and tried a number of ways to open them, including doing as the monkeys do and lifting them high above my head and crashing them to the ground. Which I don’t recommend, unless you aren’t wearing pants (like monkeys do) because your pants will get all wet. (Like mine did.) In baking, I tend to use dried coconut (also called desiccated coconut) for cookies and infusing in custards and so forth, as it tends to have a more concentrated flavor than the fresh and less moisture, which can alter a recipe.
I primarily use fresh coconut meat (the kind extracted here) for garnishing, ice creams, sorbets, and even cocktails. There are a number of devices, including wooden boards with jagged teeth and rotary devices that might be worth it if you are doing a lot of coconut. But since I only crack one coconut open every few months or so, I don’t know if I want to give valuable cabinet space to something I would only use occasionally.