I can see where you're coming from. I worry very little about levels simply because I know my dc are doing well. In the long scheme it doesn't matter whether they got a 1a or a 7a at KS1 SATS if they come out the same at the end.
If you know there's little space between your dc scraping by and "below expectations" then you may get a bit obsessive in knowing what they're struggling with, because you are worried that a poor year could have long term repercussions.
In some subjects falling behind at one point can effect later life. Dm tutors maths. Sometimes adults who have no qualification in maths come to her. When she goes through, she finds that they missed (away/ill/never understood) what looks like a simple concept. But it has effected the child, and then the adult to be convinced they don't understand maths, so they don't try to understand and give up easily, maths becomes a closed book just because of a year they struggled during.
Another problem with a report where no level/stage etc. is that as parents very few of us know where they should be. Again dm has had to have difficult conversations with parents who have been used to reports saying "He can now count to 100, and add single digits. He's worked very hard and we're very proud of how well he's doing".
Teacher is viewing that this dc has done very well considering maths is difficult for him-parent reads it as dc is top of the class in maths and isn't being stretched, and doesn't realise that what is written is low level for a year 5.
Unfortunately levels are not perfect in this-having had a couple of awkward conversations where a parent has obviously got the idea that their child is in the top level for the year, when I've been aware of children in the same year scoring a full level above that.
I've been thinking that next year I might do a chart on people who ask "how good is this level in year whatever?" because people joke on here about that is usually a stealth boast as the dc is usually doing very well. It would be interesting to see what proportion of questioners do have children that are at the top end of where you'd expect.