If the chosen permanent is copying something else (for example, if the chosen permanent is a Clone), then your Malleable Impostor enters the battlefield as whatever the chosen permanent copied, with the stated exceptions
It depends on your format and strategy
But the cards Nomura highlighted show how Wizards artists often took a different approach
The Commander Legends: Battle for Baldurs Gate Bundle contains 8 Commander Legends: Battle for Baldurs Gate Set Boostersthe best boosters to open just for funplus exclusive accessories, with 40 basic lands (20 traditional foils and 20 nonfoils), 1 traditional foil promo card with Bundle-exclusive alternate artWand of Wonder, 1 oversized Spindown life counter, 1 card storage box, and 2 reference cards
Jumpstart -designed rares, uncommons, and commons can be found in non-foil and traditional foil in Set Boosters, with only non-foil extended-art rares found in Collector Boosters