#2. To tease a possible stipulation
It was AJ Styles who vowed to make The Undertaker rest in peace and that could be a direct indicator of what's to come. Character change and storyline aside, it's been a few years since The Undertaker had a stipulation match at WrestleMania.
At WrestleMania 32 in 2016, he competed inside Hell in a Cell, while WrestleMania 33 saw him compete in a No Holds Barred match where he lost. He wrestled for roughly 105 seconds at WrestleMania 34 against John Cena and it's been a while since he had a stipulation match.
The way Styles phrased it, we could see a situation where the contract is signed for a Casket match. We like the idea of a Casket match between the two since The Undertaker can win the match while protecting Styles.
Not that getting pinned will affect him very badly, but it's a more entertaining stipulation to have the match rather than a regular singles bout. Will AJ Styles be able to get a good match out of The Undertaker?