It’s because both of these events are hard-counters to most bounty hunters. Most operate on crits and debuffs, and the chewie event gives extra tenacity and turn meter for resisting debuffs as well as preventing crits on two of their team. Multi-attacks are also a big thing for BHs, but if you lay a finger on nest her counter attack will whomp you, twice if it is a multi-attack, as well as gaining even more protection per hit. The events are hard because they are anti-bounty hunter designed events restricted to bounty hunters.