It depends on how confident you are in review scores.
If you think the review scores will wow, and garner attention and possibly positively effect sales, you announce it in advance.
If you dont have confidence, you go day & date, or possibly only after launch.
That said I think Crash Team Racing will score well.
That video with the "31 stages" to showcase the game and its graphics looked pretty great, its up there wil Mario Kart 8, in terms of artyle and graphics imo.
For me, the game is already an absolute "must buy". In my mind, it's the best Kart racer of all time. I just need to know which version to buy! Leaning towards the Switch version but if the downgrades are too much, I will have to go with something else. Probably the one with the best performance (Xbox One X or PS4 Pro)
If you end up having to decide between PS4/XBO I'd suggest PS4 simply for the exclusive content, lol :P