where we use level 3 switch and where we use router

well according to me one difference is the creation of SVI in multilayer switch i mean when we use trunk on multilayer switch we just create SVI on the switch all are then shown as directly connected are allowed on that trunk but on a router we have to create subinterfaces of the trunk interface and use the same vlan number in dot1q command ( do check how to configure routers subinterfaces for vlan trunk).