Why bodyweight ratio, not a fixed number
A 100 kg bench press means something very different for someone weighing 60 kg than for someone weighing 120 kg. Strength standards commonly used in powerlifting and general strength training express lifts as a ratio of bodyweight (lift weight ÷ bodyweight) specifically so lifters of different sizes can compare progress on the same scale, rather than everyone chasing the same absolute number regardless of how much they weigh.