I’m sure it would be a good source of elemental magnesium.
My issue would be that the different forms you can kind of choose from depending on what other peripheral benefits you want (glycinate for sleep, threonate for brain, orotate for heart and performance, etc).
The issue would be that the doses of the threonate/orotate/etc. just wouldn’t be high enough to give benefits most likely (considering the blend is prop and chelate and citrate are first they probably make the vast majority of the blend).
So if you just want well absorbed Magnesium and it is reasonably priced it should be solid. If you want other benefits probably best to stick to the individual forms you’d prefer.