Daily cleaning is often mandated by the building owner in a lease agreement.

It doesn't cost them anything since the tenant foots the bill. It provides them peace of mind their asset is in good condition.

I'm personally glad the kitchen gets cleaned daily, having worked places where employees were responsible for keeping it clean. That was a disaster.

I feel like wiping the desks down weekly would be enough. Maybe there's a reason behind it. Keeping cold from spreading around? Who knows.

Probably it's just to provide a clean-feeling workspace. It's nice to start a day and the coffee machine is clean and the trash bins are empty - especially the latter is important, given that food waste etc. can quickly develop a nasty smell.