Hi-Rez Studios are fully committing to the crossplay and crossplatform progression idea as they released the features for Paladins already, with integrated leaderboards, and are preparing to do so for Smite as well as Realm Royale.
Paladins players can already choose to queue up for cross-platform matches, regardless of whether they are playing on PC, PlayStation 4, Xbox One or Nintendo Switch. Yes, Sony's garden walls are slowly being taken down as more and more games get crossplay with PS4.
Furthermore, Paladins now also fully supports cross-platform progression which is a policy that many of the new and old games seem to be adopting.
As for Smite and Realm Royale, these two games will get merged player bases soon as well. Paladins cross-platform support went live on 11 September 2019, Smite will get the same support on 17 September while Realm Royale will be treated to these features in early October.
One question that probably bugged everyone is whether the leaderboards would be separate or merged. Well, the official FAQ states there would be a global leaderboard that will track all players, regardless of their control scheme. Hi-Rez didn't explicitly say so, but it's possible we will get filters in order to determine the highest-ranked players per platform or per input scheme.
The answer for the question about matchmaking is not entirely transparent though. It features a generic PR response in the first half, stating that the developers will constantly review and optimise the system for the best possible enjoyment etc. The second part simply says "regardless of input method" which might mean the early iterations of crossplay may just throw everyone in the same bucket.
Paladins' crossplay with PS4 is still young and it remains to be seen how well the console vs PC interaction will work but it will certainly be a good thing for the queue times. The more players, the shorter the wait for everyone.