If you have body armor that fully covers a person and rarely or plain cannot be penetrated by small arms that is a distinct and major advantage. Yes of course RPGs and anti-tank guns and a gorrillion explosives exist, no shit, but the same way guided anti-tank weaponry existing doesn't make tanks obsolete, the fact that it's not invulnerable doesn't make it useless or negate the fact that it can in fact stop most small arms. Don't think warhammer armor, think 10-20mm of plate that's assisted by motors.