Why does the Spectrum Analyzer does not have a Ground Strap

Hello,
I had a small doubt regarding the Ground Strap. Why does a VNA have a ground strap, for grounding the user who uses it.
Similarly why not have a ground strap for a instrument like a Spectrum analyzer or an oscilloscope. I would like to know the purpose of having a ground strap for some instruments, but not have it for the other instruments.
Thank you

Ground straps are used as ESD protection, mostly in low-frequency instruments and devices.
Some VNAs operate from low frequency and their inputs are vulnerable to ESD. Few spectrum analyzers work down to less than 10 kHz. Using a good coaxial connector is then enough for ESD protection.
If your environment can generate ESD pulses, add a grounding strap to ALL instruments you use. Older spectrum analyzers used input mixers that were very vulnerable and often burned out. MOst often by applying DC to their input.

Make sure you use a high-pass filter and add a grounding strap for safety.

Few clarifications needed:
1) Does ESD protection is needed only for those instrument which are capable of doing very low frequency ranges. I do not understand the relationship between the ESD and the low frequency range of the instrument. Please elaborate on this point.

2)By good coaxial connector you mean, that if the coax cables are connected properly to the instrument like VNA or SA, the ground strap may not be needed?

3) Are there any set guidelines or specific weather conditions only during which ESD pulses are likely to occur. I do not know any specific weather conditions to say that ESD may happen. I do not understand ESD that well.