I am someobdy who has employed different childminders over a period of 11 years and seen different styles.
Our first CM was a woman of whom I am sure the OP would have approved. She was incredibly conscientious, she had all the certificates, had read everything and spent all her day on worthwhile activities. We were getting absolute maximum value for every minute we paid her for.
The problem was, it wasn't very good for our children. We started noticing that they were always tired and grizzly at picking up time. Then they started not wanting to go. Then they started seeming really unhappy when her name was mentioned.
When dd was old enough to articulate how she felt we realised what the problem was. Not that CM was unkind or cruel, nothing like that at all. But they could never relax in her house because she was constantly breathing down their necks. Constantly minding them. Constantly expecting to do things with them.
It may have been giving us maximum value, as her employers, but it was very hard work for young children.
We changed to a more relaxed CM, the kind who maintains a balance between interesting activities and not-doing-very-much-at-all, and everybody was a lot happier.
I really can't understand the posters who compare a CM's work with that of a cleaner or and office worker. Carpets are not young children- they can stand being worked on a lot more intensely. Though if you cleaned the carpets non-stop for 8 hours 5 days a week, even they might start looking a bit the worse for wear
If you work in an office, your work has been designed around the assumption that it can be done non-stop for a normal working day; otherwise, your employer would not have employed a full-time worker to do it. YOu do the work and then you stop.
Child-minding is different; someone has to be around even at times when you can't do much with them, and that is part of the CM's job, as much as of the SAHM. You can't cram all the active minding into an 8 hour day, by being more intense.