Why does a microphone need a shock mount?
The function of a shock mount is to prevent vibration traveling up the mic stand from getting to the diaphragm of the mic. If you have ever recorded with mics set on stands on a portable staging system, then you will know how bad things can get.
Some microphones are naturally more prone to this kind of noise than others and need a shock mount to guard against even a small amount of vibration. Other mics are less sensitive and rarely need any special treatment.
It has to be said though that a shock mount can be an expensive accessory, if not supplied with the mic. They can be fiddly to use and not nearly so handy as a simple stand adaptor, clip or swivel mount.
In a home recording studio, it is actually quite unlikely that a shock mount will provide any benefit at all. There is absolutely no reason why you should not record without one, with any mic, as long as there is no stand-transmitted vibration.
If you are in doubt, set up your microphone. Set your preamp to the amount of gain you would typically use for vocals. Start recording, then walk around the microphone. If you can hear vibrations on playback, then you need a shockmount. If you cannot hear vibrations, and there are no subsonic frequencies visible in the waveform display, then you don't.
Sometimes I think that shock mounts are used because they somehow look more 'professional'. Actually this might not be a bad thing. If you invite a vocalist into your studio, they will sing better if they are impressed with what they perceive as the professionalism of your setup.
But if you're working on your own and do not suffer from stand-transmitted vibration, you don't need a shock mount. So you can save yourself some expense and unnecessary messing about with elastic and still end up with perfect recordings.
And if you're working on your own, your studio doesn't have to look professional, it just has to sound it!