I think it is about as close to a perfect trade as possible now. They each bring their own faults with them, but their positives are what each team desperately needs. Now, in normal times, Simmons would be worth more, as his lack of shooting can hypothetically be fixed. You can try to make CJ better on D, but you can't teach size.
After this series though, I think 1 for 1 makes sense, as Simmons perceived value is probably lower than it should be. If I'm the blazers though, I'd have no issue throwing in a pick as well.
Imagine the PnR game with Dame and Simmons. Think Steph and Draymond.