[Vinnl]

I would imagine that to be Firefox itself and Firefox for Android/iOS. I've seen people easily set up syncing on Google Chrome because they already have a Google account to which they might even already be logged in, while they're completely unaware that Firefox has a similar feature.

If you already have a Firefox account, the barrier to using Firefox Sync is lower, and with that, the barrier to using Firefox for Android/iOS is lower.