In the realm of web-apps though, unqualified tyre-kickers i.e. people who just try the demo, have an almost non-existing cost (a bit of traffic and a few system

In the realm of web-apps though, unqualified tyre-kickers i.e. people who just try the demo, have an almost non-existing cost (a bit of traffic and a few system transactions). So I can't see why you would sacrifice more potential customers (higher funnel throughput) for an artificially higher conversion rate. I mean the conversion rate is just a metric. A conversion rate of 5% of 1000 is better than 10% of 400. The goal must surely be, at least as long as the cost of serving a tyre-kicker is almost nothing, to get as many to try as possible.