MTG Arena now has its own cards to deal with, so youll find cards there you cant get elsewhere - and they have to be designed as well, which surely puts more pressure on the teams doing so
Because of this, the card reads as an Arcane Signet as opposed to the Arcane Signet, although it is not a legendary artifact
I also dont know that a Standard format that allowed all of these cards would be good idea, and I dont know if things would be better if some part of the designed process changed to account for this, and whether thats good or possible
The idea is that you get it down for free and then Pod it into something obscene
This can have a huge impact on the game, and its modality means you can always choose only the things that hurt your opponent more than they hurt you
Again, you are spending that mana, but this time you are in the color of ramp in Green