Upgrading can make your deck stronger, better for your preferred playstyle, and of course more fun
Once you find a way to lock down the board, use cards like Massacre Girl, Known Killer, Black Market, Morbid Opportunist, and Gisa, Glorious Resurrector to pull ahead and dominate the game
What makes them stand out though is the ability to open an attraction on death, which, especially if it becomes looped, can swiftly generate a storm of resources for their controller
Boom, thats a plan
Meanwhile, Teferi, Time Raveler isn't really a finisher, but it is a good way to close down control deckswhich seem to be very popular on Magic Arena at the momentby making them play at sorcery speed, which locks down all of their counterspells and forces our opponent to use their removal at inopportune times
These are my main two concerns for the potential problems of white copying