What do examiners mean by this?

I recently did a few C2 papers and some of the trig questions said "Solutions based entirely on graphical or numerical methods are not acceptable". I'm confused as to what this refers to as I use the CAST diagram and sine/cosine graphs to find my solutions.

If you use the graph and CAST diagram, you are fine.

All that means is that, as the above user said, you cannot use methods like iteration or look at where graphs intersect to score marks.

I "think" it means you can't just put numbers into your calculator until it works, or look at the graphs intersections and guess until it works, we learn the general formula and I've never had issues with it when it came to mark schemes.
Just have a look at the mark scheme to see if your method is fine, it most likely is.

If you use the graph and CAST diagram, you are fine.

All that means is that, as the above user said, you cannot use methods like iteration or look at where graphs intersect to score marks.

Is it alright if we only use CAST?