I thought that professionals had a (self-standing) spectrum analyzer device as a common tool in their toolbox (rather that relying on whatever is built in the device they are installing), just like the rj45 crimper (I am not familiar with any AP/router/switch coming with a built-in crimper).
It would be a very handy feature for home users, though.
Wireless conditions change constantly. A spectral scan at the time of install is utterly worthless over the lifetime of the device. Additional radio's go up and start interfering on your once-clean channel, your speeds plummet with a lot of packet loss, higher latency due to retransmissions etc. You have zero visibility of this on MikroTik so you are just guessing what the problem is, and you're also guessing what frequency to move to
Spectrum analyzer on the device itself is often more useful for the above reason, but also because you often use a directional antenna not an omni
I'm not interested in neighboring signal levels on a 360 degree scan, there may be huge interference from behind the radio but the dish can be 'deaf' to the vast majority of that noise, thus effectively a clean channel in the direction its pointing. This is evident when doing a scan on the device itself, but completely different if doing it with another device in proximity using an omni antenna