This is really cool! I noticed a few things you might be interested in: It looks like there might be issues rendering mana costs that have, e.g., 1GG where it does not render the second G. That is to say, it's rendered but only the barest left edge can be seen. This appears to only be the case if the card's name is sufficiently long (I noticed this with "Bethen, Cenn's Heavenly Sleep"). That being said, I have no ide…
It's not necessarily redundant or useless, there are some cards that will trigger off exiling permanents, or count the number of permanents that have been exiled during the turn to change how powerful an ability is, so if it was destroyed in battle or kill-spelled and instead exiled, it would be more useful than it simply being destroyed unexiled since it would trigger the ability or increase the count of permanents exiled that turn.