BTR4 is generally considered to be one of Ukraine's most capable platforms, but very thin in number. They were thin in number at the start of the 2022 invasion and suffered what seemed to be heavy losses despite their effectiveness. Who remembers those videos showing the thermal screens inside a vehicle absolutely massacring Russian infantry and pounding their armoured support? Those were from a BTR4 in Mariupol.

Their deployment in this fashion is really good to see as it means that Ukrainian commanders either feel that they're going to be successful in strengthening and widening their bridgehead or that they've been able to ramp up production and are able to afford the losses of the type by risking it in these types of high risk missions. Or both.