Access to waters that are otherwise difficult, or preferably, impossible to fish. There are more fishermen without a "craft" than there are with one, so naturally, inaccesible waters have less fishing pressure. Often you're allowed to fish from float tube, kayak or pontoon boat where you're not allowed to launch a boat, or where motors are banned. Water with less pressure are better - most of the time. A craft also simply gives you access to remote parts or parts of water that require impossible wading or simply long walks. Like the pike video I upload some time ago? That water is inaccessible unless you have some sort of craft. You can wade the shores, but a craft makes the options limitless.
Especially the float tube and the pontoon boat are extremely comfortable to fish from. Basically you're fishing from a lounge chair all day (see the picture :-), and who doesn't like that?Once on the water you don't have to carry anything. All three types of craft can pack more than you need for a days fishing (or even two or three) including food, water, tackle, camera and if you're so inclined, a tent, sleeping bag and mattress. Again, opening for more possibilities and a totally different kind of fishing trip.
3. Catch more fish (?)
You will (at least I do) catch more fish if you have the option of using one of the above mentioned crafts - at least for certain types of fishing. See no. 1 - you can access more water with less pressure - that alone will lead to more fish. Simply accessing more water will. But even when I fish water that I could also fish wading, I catch more fish from the tube/pontoon/kayak. I don't have numbers, but it' obvious that fish are less scared by a person in a float tube that a wading person. I've had so many takes 4 feet from the tube - much more than I have at the same distance when wading.
Hey - I'm not one to pass on an option to get more gear...
6. Cost effective
We can all go overboard and go crazy, but all three options (depending on which makes and models you buy) are usually quite a lot cheaper than a boat. The take up less space, they're easier to transport, and you can basically launch all three versions from anywhere. No need for a boat ramp, a big trailer or a 4wd to launch.
It's odd, but even after fishing from different crafts, I still deep down feel as if I'm cheating a little. Oddly, I don't feel that way fishing from a boat, but any craft - a little cheating? Still, after nearly 20 years of using these crafts, I feel a little more proud getting a nice sea trout from the shore than I do from the tube/pontoon/kayak. But hey - it's easy to get over :-).
Have a great weekend!