They're heavy, expensive, conspicuous, take time to set up and take apart again. In short, tripods are a nuisance. And in this age of digital cameras, we can always increase the ISO sensitivity to accommodate a low light situation. So why bother with one at all? Let's look at some of the advantages of using a tripod.
Fist of all, what is noise? Increasing the ISO level in a digital camera amplifies the signal through the digital sensor that records the image. This is much the same as turning the volume on your home stereo up to 10. You will hear a hissing in the background. This is amplification noise. It looks like grain in a low quality film would and decreases the quality of the image in the same way.
The technology used to make digital cameras advances almost daily. One day, hopefully soon, digital cameras will be created that can record the same quality image no matter what ISO setting is used. But until then, we just have to leave the fact that if you want a better quality image, you need to use a lower ISO. If you want to shoot in low light or at night, there are a couple of options.
Firstly, you could use a flash. Using flash can produce some very natural or very creative results, depending on how you use it. But there are a couple of drawbacks. Firstly, you have to buy a flash unit. In most cases the little pop up flash on your camera is simply not powerful enough to do anything more than fill in some dark areas in an already well lit scene. Flash will not work for all subjects either. It is fine if you want to take portraits, but if you are shooting a low light landscape and pointing your camera out into the vast beyond, there is little or nothing for the flash to bounce off and the light it produces will be lost. So sometimes there is no other choice but to sit your camera on a tripod, reduce the ISO and slow down your shutter speed to take in all the available light.
Like just about any other camera accessory, tripods can be creative as well as utilitarian. Think cityscapes at night with traffic trails running through the scene. Think clouds moving through a twilight sky. To capture this movement and keep the static objects in an image sharp requires a long shutter speed. So the camera needs to be kept deadly still for 20 or 30 seconds or even longer. It is just not physically possible for a human to do this, so the only thing for it is to drag out the tripod, perch your camera on top and use either a self timer or cable release to take the shot.
Depending on what you want to do with your images, you will either regard your tripod as your best friend or big annoyance. If your photos are destined for web use or maybe small prints for a photo album, you might not be as concerned with the technical quality of the end result, but if you want to enlarge print to hang on a wall, or are looking to sell your images, you will soon discover that a tripod is a valuable tool capable of being the difference between getting that million dollar shot or missing a golden opportunity. I carry mine just about everywhere.