I'm recycling my old iMac. So I didn't reinstall the OS after erasing the hard drive. No reason to, it seems. Am I right?

Old iMac from 2015. Can't get any trade-in credit in Apple Store. They sent me the UPS label for recycling.

I went through all the steps I'd do if I were getting it ready to sell to someone else. But I stopped before reinstalling the operating system because no one is going to be operating it. I assume it will be disassembled and recycled.

Any reason to not proceed this way?