Given what's been shown of the game, it'll need all the help it can get.
People should be hoping this is opt-in/opt-out, and that the leaderboards are both unified and per-platform. Hacking and cheaters on the PC side can definitely deter the online, it's happened with Forza Horizon 5 as an example. MS and Arkane should have some countermeasures to enforce in nullifying that problem.
If they don't, the game will be dead within weeks, and that's assuming the final release is enough a bump over what's been shown before to make for a more compelling offering.