That's the basics of the Pokmon trading card game
This is by no means a practice I believe should be used in every set, but I think invigorating a tribe like mercenaries and allowing players to discover that Doomed Necromancer is itself one, can be a fun moment that rewards deck builders taking the time to look for hidden gems
Again, no point in struggling when this can help
Onslaught, 2002: $1,283 Onslaughts original fetch lands are the ONS ticket here, with Polluted Delta fetching among the highest prices
Once your Humans are all in play, you can clear the battlefield with Taunt from the Ramparts, goading all your opponents creatures and preventing them from being able to block, opening the way for your creatures to sweep through