if you prune you are then offering less network decentralised security service for the peers. as you no longer become a FULL node source of blockdata for new peers.
But it's better than not being a source of data at all.
in torrent terminology being a leecher is better then not accessing torrents at all.. but being a seeder is best
seeders add to the decentralisation of the torrent network
leechers just take from the network and cause more pressure on the seeders
dont pretend to be a full node if you disabled full archive and also not fully validating every byte of all blocks