Few dumb? question about mt7530 / rb750gr3 / DSA

Hi to all

i am (still) confused with DSA. If i am reading it correctly, with DSA every eth port is exposed as stand alone. This behavior is same as RouterOS

OpenWRT=RouterOS
WAN=ether1
LAN2=ether2
LAN3=ether3 ... etc

ok, so first question:
after tryout of v5.x kernel and DSA, something is still unclear
why eth0 is still exposed? it is normal?
On my rb750gr3 i have WAN,LAN2,LAN3,LAN4,LAN5 (as expected) and there is eth0
What is the use of eth0 if every port is independent?

and second question
on RouterOS the MAC addresses are
ether1 = MAC
ether2 = MAC+1
ether3 = MAC+2 ... etc

but on OpenWRT LAN2,3,4,5 have same MAC ??? which is from my point of view wrong if these ports are independent

so, in DTS, maybe this should be changed?

&switch0 {
        ports {
                port@0 {
                        status = "okay";
                        label = "wan";
                        mtd-mac-address = <&hard_config 0x0010>;
                        mtd-mac-address-increment = <0>;
                };

                port@1 {
                        status = "okay";
                        label = "lan2";
                        mtd-mac-address = <&hard_config 0x0010>;
                        mtd-mac-address-increment = <1>;
                };

                port@2 {
                        status = "okay";
                        label = "lan3";
                        mtd-mac-address = <&hard_config 0x0010>;
                        mtd-mac-address-increment = <2>;
                };

                port@3 {
                        status = "okay";
                        label = "lan4";
                        mtd-mac-address = <&hard_config 0x0010>;
                        mtd-mac-address-increment = <3>;
                };

                port@4 {
                        status = "okay";
                        label = "lan5";
                        mtd-mac-address = <&hard_config 0x0010>;
                        mtd-mac-address-increment = <4>;
                };
        };
};

this way i get a proper MAC addresses unique for each port, same as on RouterOS

but maybe i am wrong? any suggestion?