If you've read my reviews of the Tentacool cards from this set, you'll know that the first one in this set was pretty poor, having a below average HP, and only one move that forced you to move Tentacool and all cards attached to it back to your hand after attacking

SM - Team Up Latias and Latios GX Alternate Full Art $999.00 Market Price: $1,950.33 Gengar and Mimikyu GX Alternate Full Art $900.00 Market Price: $1,263.09 Magikarp and Wailord GX Alternate Full Art $700.00 Market Price: $800.56 Gengar and Mimikyu GX Secret $300.00 Market Price: $332.76 Gengar and Mimikyu GX Full Art $200.00 Market Price: $283.12 Eevee and Snorlax GX Secret $199.95 Market Price: $224.69 Eevee and Snorlax GX Full Art $179.00 Market Price: $217.63 Gengar and Mimikyu GX $149.24 Market Price: $254.36 Pikachu and Zekrom GX Secret $130.00 Market Price: $204.78 Sabrinas Suggestion Full Art $130.00 Market Price: $170.62 Latias and Latios GX Secret $110.00 Market Price: $170.52 Pikachu and Zekrom GX Full Art $103.25 Market Price: $139.06
Sure, you can get some mileage out of Acidic Slime or Eternal Witness but if you're going to do the work to make something into a token, you should be able to stack its ability and not have to squander it in a sometimes fruitless attack
Promotional cards don't have a rarity assigned to them like all the cards you pull from the in-game sets
It also affects the layout for design and artwork to provide the best opportunities to display your brands marketing details