For me, I had iMessage which is end-to-end encrypted, and I can count on one hand the number of texts I send to non-iPhone users in a year. There was no value to changing, and no need to try and convince everyone I know to switch to a different messaging service.
And with Facebook owning WhatsApp, even with end-to-end encryption, there are trust issues there. I had WhatsApp on my phone from a trip to India. About a dozen of my friends in the US showed up in there, but we never used it to talk. Once Facebook bought it, I deleted the app, and nothing of value was lost.
If I really wanted secure messaging with someone I talk to often on Android, I’d opt for Signal over WhatsApp.
I never heard of TextSecure.
Signal before it rebranded.