The phono cartridge contributes to unwanted noise as well. It is a sound transducer and can be thought of as a specialized type of microphone in that it picks up the vibrations from the stylus as it tracks the record groove and responds to its encoded vibrations.
Unfortunately it can also transmit the vibrations from any noise that it picks up. This includes your footsteps on a wooden floor or any noise including your voice! You can actually record your voice by talking very loudly and very closely to the phono cartridge.
Isolating the noise generated from the turntable’s motor from the platter is essential. Low frequencies are particularly vulnerable to being picked up because of the very nature of the recording and playback process of records (see article on preamps and the RIAA curve).
This means that low frequencies are over amplified on playback of vinyl records so your cartridge “hears” them much louder than high frequencies.
Ideally your turntable would set perfectly balanced on a 2 ton slab of stone inside a soundproof, dustproof enclosure and would be driven by a noise free source. OK, that’s a bit much, but it is the direction that you should be thinking when choosing a location to set up your turntable.