Common thought is that the Bucks front office were reacting to Giannis public comments about possibly leaving which pressured them to trade for Jrue in 2020 and Dame this year.
I think it's actually just as likely that Giannis planned on signing, but by casting down on his future in Milwaukee it raised the value of the Bucks future picks and maximized their trade offers.
Does New Orleans take the Bucks deal for Jrue is they know he will be in Milwaukee longterm which devalues all their future 1sts?
Less so for Dame with only one pick, but still is a factor.
Giannis can obviously communicate this stuff internally to Horst and the org. They will undoubtedly know his position and what it takes. Media has also said Bucks have been checking on Dame for quite some time.
The other benefit, especially in 2020, was making other teams feel like they had a shot at Giannis and potentially mess with their future plans to keep cap space open.
He called their bluff, the bucks literally signed his entire family, will take time for another team to go that distance.