Phone GPS can have L1 L2 L5 these days. There’s unlikely to be much of an advantage. Phone GPS also has traffic data. And you’ve got multiple apps that compete

Phone GPS can have L1 L2 L5 these days. There’s unlikely to be much of an advantage. Phone GPS also has traffic data. And you’ve got multiple apps that compete and keep evolving unlike most car systems. The standalone GPS have a place but I suspect they’re a tiny minority for in-car usage compared to phones.