I do realize this is the honey bee forum .. but I can't seem to find a general forum on insects... so forgive me!!

I am growing elderberries & find the VELB (valley elderberry longhorn beetle) is found on this shrub & the beetle is considered protected & important where ever I read about it & the elderberries. My ? is that I have not found anywhere WHY this beetle is important & I assume is not a pest? Thanks for my posting on this site in hopes someone can direct me to the proper forum!