At first, Mark hadn't been sure of using the Vine Centipede. Not all of its abilities were offensive, and his need was an offensive demonic trick. Was using the Vine Centipede the good choice?
But Yuri's opinion made him tilt more towards it.
"If you gain the Vine Demon's powers, you will gain its Resistances, too. Most of its abilities are rather good, in my opinion at least."
Vine Storage, Vine Manipulation, Parasite, Sap of Sleepiness, Barrier of Non-Escape—none of these were bad. Even Vine Storage would give him a storage ability. More than that, he would have a Resistance to Plant Poisons, too.
Whereas the Minotaur was not that good except for its ability to have a stronger body. And this was not the be-all-end-all scenario either. If it failed, Mark felt he could get a new ability someday anyway.