if you can get get pallets and can keep them out of the landfills then using them is a good thing. use the good one for building things, ie, fences,
compost bins, etc. broken ones can go to hugelculture. when the good ones start to breakdown, you're got the start of a new bed. pallet wood can be mixed with logs, limbs, etc to make the bed. pulling out a few nails is no big deal.
not utilizing pallets and sending them to the dump and then cutting down trees to build hugelculture beds seems un-permaculture to me.