Is Instapage worth the price premium over Unbounce?
Only if you will use what the premium buys: AdMap-driven personalization across a large ad account, enterprise collaboration, and high-volume page production. A team running twenty landing pages with simple keyword insertion will see little return on the difference. A team managing hundreds of ad groups with dedicated page experiences typically will.
Does Smart Traffic actually beat normal A/B testing?
On heterogeneous traffic, usually yes. Instead of declaring one global winner, Smart Traffic learns which variant converts best for each visitor profile and routes accordingly, which captures lift that a single winner leaves behind. It needs meaningful traffic volume to learn, so on low-volume campaigns a classic A/B test remains the right tool.
Can I build a full website on these platforms?
They are designed for campaign landing pages, not full sites. Both can technically host multiple pages, but navigation, blogs, and content management are out of scope. Teams that want one tool for a full marketing site plus landing pages usually look at Webflow or Framer instead, trading some conversion-specific features for site-building breadth.