It doesn't match the Bokai Observatory, but you can see a slice of the city of Osaka. It's a gentle uphill, so I think it's fine to climb on your way back from Otaki.

Today there were red-rumped swallows and an eastern crowned warbler (just its call). Couldn't capture them on camera

On a clear day you can take in a view of all of Osaka City. There's one bench where you can rest. There's no roof, though.