I’m no tech expert and I haven’t done this for a while so don’t know if that change but they were more packet loss/errors (not sure proper terms, not English native). For most files this isn’t an issue but was for more sensitive ones like programs/iso…

Battery also suffered more from this used, keeping phone charged while tethering wasn’t good due to battery management system. But things could have changed.

Last point is that bad weather does affect cellphone reception.