It's a perfectly fine thing to do if your refrigerator or washing machine has software from a company that (1) has sufficient expertise to do software well, (2)

It's a perfectly fine thing to do if your refrigerator or washing machine has software from a company that (1) has sufficient expertise to do software well, (2) prioritizes keeping it secure, and (3) commits to supporting it for the entire usable life of the appliance. But usually 0 out of 3 of those are true. The devices come from companies that specialize in hardware, so the software is usually an afterthought. They don't prioritize keeping it secure because they know customers are more interested in features like whether the refrigerator's shelf configuration or the washing machine's capacity. And they don't commit to supporting it for the lifetime of the product because once they have your money, they have little incentive.