I figured that it had something to do with health insurance. The only tax reason that I could think of where it would be advantageous to not exclude the unemployment compensation is if excluding it would disqualify you from receiving a 2020 Premium Tax Credit because doing so brings your 2020 MAGI below 100% of the federal poverty line and you received no Advance Premium Tax Credit for 2020. (Probably an unintended side effect of this exclusion.)
I'm not sure how reducing your 2020 MAGI would affect the cost of 2021 or 2022 health insurance since the application for APTC requires you to estimate your 2021 and 2022 MAGI. In your estimate of 2021 or 2022 MAGI you would not exclude unemployment compensation.
