I'm a PA to a CEO. He travels around the UK a lot so it works well for us as we naturally wouldn't often be in the office together, anyway.
I like the flexibility of being able to drop DS off at nursery whenever he wakes up. I work flexi time so can clock in and out, so long as I do my contracted hours which I do more than.
I have no time lost to commuting, and because of that, they get more time from me. If I was travelling in, they'd get 1.5 hours less from me each day (this is where the over and above of my contracted hours come into it).
As somebody else mentioned, it's great to be able to hang laundry out, take in parcels, wash the dishes in my lunch break, or I'll clock out for 10 minutes if I hear the washing machine ping and I'm not on lunch. Again though, that's only because I have the flexibility of working flexi time. My partner works from home and is in meetings/on calls all day long, so doesn't have the flexibility to be able to clock out for 10 minutes aside from his programmed breaks.
For me, it really helps maintain a work-life balance. Being able to keep on top of the small things like a few dishes, or a load of laundry, means I'm not doing everything in the small window of time I have from picking DS up from nursery to bedtime.
I do think it probably depends on the type of worker you are, though. I get very distracted in the office - I am a chatterbox and will get drawn into conversations whereas I don't have that distraction at home. I'm also not the type of person to be precious about counting the hours and minutes I've worked; I just wake up, shower and start work, and work right up until I need to pick DS up from nursery which is usually 8am - 5.45pm, whereas I only need to work 8am - 4pm to work my contracted hours, so I don't feel guilty about any small amounts of time spent away from my desk taking in parcels or hanging some washing out, because I know I give back more than I take.