I've worked 0.6 since I had my kids. Eldest is now 13 and I have no intention of upping my hours. DH does 0.8.
We found the kids were more tired with school/after school than with nursery - more than 1 setting, more expected of them during the day at school.
The kids needed downtime at home, earlier dinner, a more relaxed evening before bed. The 2 days they're in after school and we're both working were always hectic and they were shattered. Having a few afternoons with a parent at home also means time for playdates with friends, planning appointments so they weren't always in school time (e.g. speech therapy), homework when they're older, instrument practice, and just being together.
On my two days I get a lot of stuff done in the house or garden, as well as my own work (teacher so marking/planning), study (did a part-time MA a few years ago), planning of numerous appointments (dentist/ortho, psychologist, medical appointments), errands like food shop, and also get some down time.
We can now leave DS1 as he's in secondary so lets himself in 2 afternoons a week but they still need us a lot practically, emotionally and to help with supporting self-management and development (ND family). We also both share the mornings so no breakfast club but always 1 of us here till youngest leaves the house at 8:15.
I live in a country where it's very very common for parents to work part-time and continue to do so even when kids are not in primary any more. Less than 20% of staff in my school are full-time!