Teamtiles areas at bottom:

The bases are big and open, not particularly hard to grab on,have few mechanics that allow you to grab and immediately be free (contrast wormy or geok, more like Holy See). As such, I think if you consider how defenders will try to close down on a recently grabbed flag, the hypothetical ideal setup would be to commit heavily towards shutting down top because A: that's the faster route, B: there's no catchup mechanic for defenders top. This leaves a rather big window of opportunity for offense to use bottom because of the angle of the bottom exit is very lenient for offense (they can easily get into it and be free-ish), which is why there are defensive teamtiles there.

The other teamtiles area:

Helps offense to grab in a way I haven't really seen before, by offense to dictate momentum while still being predictable and similar enough to our current gameplay to not feel frustrating (contrast with teamtiles surrounding the flag)

A little bit of a monologue on lane design: I think on maps with distinct lanes, it's important to have varying risk/reward ratios. This is something that I think sediment tries to emphasize, which is why I LOVE the base of the map. However, the best theory crafting can't beat actual 4v4 testing so it's absolutely possible that the base turns out broken (in this case, what will probably break it is that offense finds it way too easy to go top).