A lot of teams add 3D to a marketing site too late in the process. By the time engineering sees the concept, the experience is already sold internally as "immersive." Then the practical questions arrive: Can this load fast on mobile? Does it still work without a high-end GPU? Is the 3D interaction helping the buyer decide, or is it just decoration? What happens to accessibility, analytics, and conversion tracking? The healthier way to scope immersive web work is to treat WebGL like product behavior, not like a visual layer. The quick decision tree Use 3D when it helps the visitor understand something that flat media cannot explain as well. Good fits: product configurators spatial walkthroughs technical demos interactive feature explanations premium campaign sites where memorability matters Weak fits: generic hero animations loading-heavy background scenes decorative particles "innovation" theater without a conversion path The implementation test Before building, ask three questions.…