Aside from the risk of breaking things, there's the risk of data leaks and enabling surveillance through negligence or intentional back doors.

Hardware and software companies have a story of implementing anti-user features in very shady ways (ie silent update to T&C allowing the org to track and share data with third parties and/or brokers).

I don't care if my smart Philips light bulb shares all its data with god knows who. My router? that's the device that manages all connections including critical ones. I want it to be impeccable and transparent. That's why I refuse to buy from manufactures that require a could account like Eeroo or that require weird connections to work properly like Tenda (a friend had a Tenda mesh and it wouldn't work if we blocked connections to Baidu, Weibo and others)