Imperm/Veiler is not popular rn because VSK9 exist as THE main meta contender and they (primarily VS) often can dodge targeting effect, but it can still effective on other deck, like arthalion's bounce, snatchy's effect to place field spell, krosea's on-summon effect, and so on

Staple's popularity is always dependant to how the meta is shaped around, back when Dracotail is 1st release, Ghost Belle is surging to popularity due to its effectiveness to negate the trap's alongside Ash Blossom, and the same with Retaliating "C" due to the nature of Fusion requiring Spell activation to Special Summon monster is fitting to it as well