Tokens are broke, count as casting a card for your opponent. See post in general discussion for full thoughts
I'd like to see the number of toxic token reinforcements at a glance without having to click on it, the infinity symbol is confusing as it doesn't show anything.
The infinite symbol on the toxin token is probably needed so that you know that it has become a permasupport, and probably for technical reasons so that other things are not able to destroy it. Only a few things in paper Magic are able to get rid of them or delay them.
But maybe there could be a solution of adding a second number at the top corner of the gem, if that would make sense for showing a support's reinforcements (or just particular types of supports).
A similar thing could maybe be done with level supports, which makes me think that toxin was done as reinforcements instead of shields or levels so that Kasmina doesn't kill herself with using her A3/L3 (increases own cards levels, and - at later PW levels - shields as well).