I think that using the lever shouldn't grant inspiration, yeah, but Idolike having the lever there. I feel like it's the only way to the underdark that the characters would really know about. Every other way in feels like metagaming that characters would only try because we the players know about them. Like the spider's lair? Why would the characters ever cast featherfall and try that route? For that matter, why would players do it if they didn't already know about that route other than to just see what happens? I also learned on the forum that if you were the hag's mask, you can take an entry into the underdark through her lair, but again, why would the characters ever find out about that? And again, why would a player find out unless they were just randomly trying stuff?
As someone who naturally loves exploration, I would. I don't always try everything but I love to have a good overview of the whole area, scout all available paths before going forward. I legit just missed that the lever could be used like this...I don't know how xD
