We don't know yet! Unless they already had insights that were denied to us.Not entirely true. I've been complaining about all the Dylan content that isn't directly tied to the Sophia/Dylan storyline. So not directly the pool event, does include it.
The Elli/Dylan relationship will have a big impact on Sophia in the future. Likewise, I can imagine that Dylan/Marie will have a role in the Dylan/Sophia relationship in the future. I just think that Sophia showed sexual interest in Marie during the yoga event. And that Marie is already cheating on her boyfriend with Dylan. So it is conceivable that she could cheat on Dylan with his mother at some point.
That L&P takes the trouble to characterize the characters through history may seem superfluous now, but may play a role in the future. Even if that future, for us, is still a decade away.
This may not please everyone, but it is a perfectly normal way to tell a story.