There are plenty of depts with a good iPad use case, typically those with very standard workflows and few apps.
Think about HR who just need Zoom/Meet/WebEx, Greenhouse (or whatever ATS), and email+calendars.
Office admin, customer support, etc. all have simple needs that benefit from a really nice, but easily controlled and secured device.
Also, don’t underestimate how much “the Spotify app works” will entice people too.
Yeah, you won’t convert all the quants, engineers, etc but they aren’t the target. That said, in my experience they love the iPad as a second screen that’s very portable, in contrast to the high powered very unportable workstation.
The biggest factor for iPad adoption is really: “is there an app”. Particularly with SaaS tools there’s often a decent which lends itself to iPad usage.