Why housekeeping is the heart of the hotel?

Why is housekeeping considered as the heart of the hotel?

I think the Front office is the heart of the hotel as that is the first and last point of contact for a guest to see and interact.

The housekeeping efforts clearly show how the hotel will take care of its guests.
I read somewhere, that HK is considered as the heart of the hotel because HK is recognized only when something goes wrong – same as heart.

I think HK is considered as the heart because the heart pumps blood which keeps the body alive and active – similarly, HK keeps the nook and corner of the hotel spic and span so that the hotel looks neat and tidy, alive & active to welcome guests.

Even though the first impression is with FO where the guest sees & interacts with a staff, but actually, the first impression is when a guest sees the property by its look on arrival, whether everything is kept clean.