Just cause I’ve seen people asking a lot about completing collections
Is now a great time to complete? Yes, all diamonds are dirt cheap (aside from the gatekeepers) if you’ve been on the fence about starting or completing collections now would be the time.
Is it worth it (this part is subjective)? For me it was, you unlock 4 of the best players in the game (Sheff, Biggio, Mantle and Wagner). I use all four so it was worth it to me. Now with all the content that has dropped all those stubs to complete these collections might not be worth it to you as you can get personal favorites/comparable cards for cheaper.
Conclusion: If collections is something you want to complete before the game dies down, now would be the time.