It allowed her to skip out on most of the family drama and competition rumors. It worked out pretty well for her.
I know I bitch about the long maternity leave (by US standards, I know), but it really is well planned. She bookended it with a royal wedding and ToC/AirForce appearances in May/June and she’ll come back in October to Eugenie’s wedding and a diplomatic reception. It subtly, but effectively, puts her in a completely different level than Meghan.