I believe there are VOIP phones that are sim card based. Imagine a country that doesn't have land lines but folks want a home phone.

There are SIP to cellular gateways which have historically been very popular in regions where landline to mobile calls cost money but mobile to mobile do not, but they mostly don't exist in the US market other than high-density devices mostly used by SMS spammers.

The only actual VoIP phone with a SIM card I'm aware of is the Yealink T74LTE which for a long time was exclusive to Verizon's business phone service but has recently become available for general purchase, those can support both SIM over LTE data and VoLTE (which is also basically SIP but over a prioritized channel).