He does seem super sketchy, doesn't he? What are those Stormstriders? Is he that helpless in stopping the Voidspren from bonding under his very nose? He handed out the visions, following the letter of the law but not the intent. Bringing the Highstorm in the face of the Everstorm...
But post-Oathbringer, as he told Dalinar of the Herald's burden it became more understandable. He doesn't understand things without a Bond. Somehow even less than other Nahel Bond capable spren.
His stinginess with information is understandable, the Sibling was hurt before, he distrusted humans post-Recreance, his understanding isn't quite human so he couldn't prioritize
As for trust, he is the linchpin of their ecosystem, he deposits crem and distributes Stormlight, and brings rain. He is vital for life on Roshar. He has been associated directly with Honor for a long time too, especially in Vorinism.