Sure, costing 5 does mean you can only run so many, unlike the Packmate which had Foretell, making it much easier to jam a bunch of them into your deck, but you should still value that first 1-2 copies pretty highly
The Gitrog Monster is a great example of this, forcing you to sacrifice a land or sacrifice itself, the upside is you get to play an extra land each turn
These cards are not intended to be reprinted in normal tournament-legal paper Magic sets, which creates long-term scarcity
Few gold star Pokmon cards are ever printed - on average you'd find one in every two booster boxes, or 1/72 packs
By rotating out earlier cards, game companies don't need to design cards that are powerful enough to draw people away from their old favorites , because those cards won't stick around for very long
Beast Whisperer can be a real game changer for you whenever it is in play