Memory estimate?

[jariji]

BenchmarkTools.Trial: 4103 samples with 1 evaluation.
 Range (min … max):  1.112 ms …  1.475 ms  ┊ GC (min … max): 0.00% … 0.00%
 Time  (median):     1.210 ms              ┊ GC (median):    0.00%
 Time  (mean ± σ):   1.213 ms ± 41.653 μs  ┊ GC (mean ± σ):  0.00% ± 0.00%

                   ▂▄▅▆▆█▆▇▅▄▄▅▂▂    ▁▃▄▃▇▄▄▅▄▁               
  ▁▁▂▂▃▄▄▄▅▅▃▅▄▆▅▆▇████████████████▇████████████▆▆▄▄▃▃▃▂▂▁▁▁ ▅
  1.11 ms        Histogram: frequency by time        1.31 ms <

 Memory estimate: 10.14 KiB, allocs estimate: 147.

I'm wondering why are the memory and allocations a single "estimate"? If the amount of memory usage varies over the samples, then statistics and a histogram could give a more complete picture.