I have used a copy of the 15-30 lens for a couple years and for my needs it has been a good lens. It is light, small, and relatively cheap. I tend to use it stopped down for landscape photography with my R5, and it does decently well in allowing sharp focus from close foreground elements to infinity.
It's not the absolute sharpest lens, and the corner performance may not be totally spectacular, but for a small and cheaper lens that I can take hiking or backpacking - along with a 24-240mm lens - I feel it does quite well. It performs better at 24-30mm than the 24-240mm lens - I know that's not surprising, but it allows me to easily swap out the longer zoom for the 15-30 when I want a bit better performance for wider angle compositions.