I take it as smart asset management. His value would not be higher (with this team) in the next two years. Might as well get the best multiple assets you can for him, while replacing him with an older, maybe less skilled veteran in free agency this summer, that's open to mentoring the kids.
I see it as the contrary.
You will trade other players within the next month that will likely bring more '22 picks. Why not spread the assets over 2 years? Especially since you have to build the scouting department back up.
I'm not questioning the value of the return here. I'm just saying that you have an interim head scout that will be making enormous decision for the future of this team. I would have preferred to mitigate risks while trading some players this year and others next year. Plus, with Toffoli's numbers last year and this one too, I think it's safe to say that the value would have been similar next season. BUT, if the team is really sold on Heineman's potential, maybe waiting another year would have made him unavailable.