Not sure I can agree, as foreign tourists cannot be separated from any other type of fan paying at the gate. An admission fee is the same regardless of who is paying it. An influx of foreign tourists would benefit the city hosting the event, not necessarily Formula 1. If your point is that Las Vegas and Miami agreed to it for this reason, then maybe there is something there. But I don't see why this would be a negotiating point for Formula 1.
I suspect it's more like Las Vegas and Miami were receptive to this arrangement because they were so eager to land the spot in the calendar, and therefore agreed to terms that favored F1. It was claimed that 240,000 fans filed in over the course of the three days for the Miami GP. I tried to find an average ticket cost for the event, but failed. Some tickets are $40, some are $28,000. If I use an average of $500 (which may be wildly off the mark) that's $120 million just in gate and before sponsorship is factored in. This is a sweet deal for F1, and far exceeds what they gave up in hosting fees.
