So here is a hypothetical. Maybe someone better with math can help me.
Farming a 2*. Is it possible?
selling a (max championed) 2* gives 65000 ISO and 125 HP [ https://forums.505go.com/discussion/45176 ]
you also earn along the way 17500 ISO, 5 Heroic tokens, 3 3* covers, 250 HP and 5 CP [ http://marvelpuzzlequest.wikia.com/wiki/Champion ]
and it costs an initial investment of 69529 ISO [ http://marvelpuzzlequest.wikia.com/wiki/Iso_costs ]
plus the 13 covers (=3250 ISO) and 5k to champion
Plus the fact you are not selling the 50 covers for 250 ISO each (12,500)
69529+3250+5000+12500 = 90,279
So after an initial investment and a lot of covers earned:
90,279 ISO → 82,500 + 375 HP + 5 Heroic + 3 3* + 5 CP
NET:
-7,779 ISO, 375 HP, 5 HT (=1,250 ISO), 3 3*, and 5 CP
added table of 2* → 4* for convenience:
Captain America → Captain America → Captain America
Daken → Daken → X-23
Human Torch → Human Torch → The Thing
Thor → Thor → Red Hulk
Wolverine → Wolverine-> X-Force Wolverine
Bagman → Spider-Man → Miles Morales
Ms. Marvel → Captain Marvel → The Thing
Ares → Ragnarok → X-23
Bullseye → Bullseye → Kingpin
Hawkeye → Iron Man 40 → Hulkbuster
Moonstone → Hulk → ‘TA’ Hulk
OBW → GSBW → Nick Fury
Storm → Storm → Thor GoT
Magneto → Magneto → Professor X
So from a general ISO standpoint, it isn’t worth it. it basically allows you to convert
7.7k ISO 8 → 375 HP, 5 HT, 3 3*, and 5 CP
Which could be worth it to the right person, or for the right rewards