Pure history
Pay 1, tap it, and tap another creature
Theres no downside to buying the precon if you want it
When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell

The intention is that we will make sure a version of that mechanical card is made available somewhere other than from purchasing directly from our site. Fast forward to September 5th, whereupon Rosewater was asked about this discrepancy via his personal Tumblr blog, in particular how WotC was able to justify keeping the Reserved List promise [which holds that, in service of preserving their secondary market value, none of its listed cards will ever be reprinted] but choosing to opt out of the Universes Within promise? In turn, the MTG lead would explain that while he understood the frustrations caused by the rocky nature of the games ever-changing release plans, rest assured, the relevant Universes Beyond cards were absolutely on the way: We promised that every original Secret Lair design would get an equivalent version available somewhere, meaning longterm you didnt have to buy a Secret Lair to get it