On paper the new Show-time Griezmann seems to be more fit for the current state of the game hence the whopping +13 in physical contact, + 5 in balance and a more balanced dribbling profile, whilst equipped with low screamer and visionary pass. He's looking to be a direct competitor to the BT version.
Now if we look past this slight powercreep, it isnt all upsides for the new Griezmann, as the build I've used for BT Griezmann is just an attempt to match the overall abilities of the new one. As you can see only 4 points have been invested in both passing and shooting so if we disregard pace, the BT version can be a much better playmaker, as well as a more clinical finisher. When you combine the hole player playstyle with his abnormally high defensive attributes, he should also be more present within the pitch compared to the show-time version (and probably will be more present on your team given his perma B form).
In conclusion, I think both these versions have there own strengths with the new one being a better attacker and the old one being the superior midfielder as neither are necessarily better than the other. If you already own the previous BT there is no need to go for this new one. However for any long-time fan of Grizzy who doesn't already own the previous version, then this will probably be his 'last' great card (albeit the same thing was said for when his BT version dropped) so now is your chance. Do remember though that players only needed to spend 1500 coins to obtain his previous version, while the new only slightly improved show-time version can cost up to 4500 coins... Yikes.
Hail the little prince!