The marketing site and the signed-in product on the same script. Trial pages, docs, pricing and the app itself report into one account, so the path from a blog post to an activated account is one funnel rather than two tools stitched by hand.
No consent banner on the marketing site. Nothing is stored on the visitor's device, so the page that has to convert is not the page asking permission first. For a product whose own pitch involves trust, that is worth more than the analytics.
Funnels, and cohorts with a caveat. Journeys show where a signup or onboarding flow loses people, step by step, and that works whatever your identity setting. Retention cohorts group by when a visitor was first seen ever rather than first seen in the period. Read the next section before relying on them, because what "the same visitor next week" means depends on a setting most people leave alone.
Heatmaps and recordings inside the product. The onboarding screen where everyone stalls is usually not the screen you would have guessed. Inputs are masked in recordings by default, which matters more here than on a marketing page.
A feedback widget you can put on one screen. Ask on the page where the doubt is, rather than emailing a survey a week later.
Reports without handing out logins. A shared dashboard is a link with no account behind it, which is how a founder shows numbers to an investor or a board without adding seats.