I have no way to know absolutely that they are strawberry anemones, only did the research many years ago when I first got online.
The SA classification was just what fit the description best.
I'm unaware that they are even sold as they can't be removed from the rocks and they never grow large. The largest I've seen would only be about the diameter of a quarter.
Mine never get to dense colonies with only one or two in most spots, but they are fairly strongly coloured so they are noticeable when they show up.
I don't know if they move around or what because I go a year or so with quite a few and then another year or so I don't see any, or at least very few, but they come back again. They seem to prefer the lower light areas of the tanks they are in.
After I moved the live rock from the seahorse tanks and placed it in the sumps, the anemones are no longer seen in those tanks at least, so they don't like no light at all.