I guess this way the tournament can ensure one of their biggest drawcards will stick around til the 3R. Not protecting her too much by making her a top 8 seed but still protecting her enough from drawing a seed in the 1R. If she was unseeded she could've drawn Halep or Venus in the 1R which whilst would be a popcorn match, would mean they'd lose a huge drawcard early.
You got that backwards.
The organisers are protecting the top 8 seeds from Serena.
By seeding her (that high), they ensure that none of the top 8 (presumably a crowd drawing players) will get eliminated early at the expense of Serena advancing, and test her if she is in good enough form to make the women's tournament interesting.
That way, if she's not in good condition to go deep in the tournament, she will probably get knocked out earlier, thus naturally not being a problem for the other potential top seeds to advance further in it.
Can you imagine the scenario, where Serena draws Halep/Muguruza, eliminates her, and has nothing in the tank to continue with her run, eliminated in R2 or R3?
It will be a pretty awkward situation.
