> this doesn't seem to be accurate

It is pretty accurate here, case #3 is significantly (almost two times) slower than case #1.

Not on my browser (Safari 16.1). Here case #3 is the fastest, over 7% faster than case #1.

Seems like Safari has quite naive element.append(...list) implementation and/or "destructuring to argv" operation is slow there.

I suspect that element.append(...list) is just a

   for(auto arg : args) 
     element.append(arg);

so no transaction there at all - slower version of case #3.

On Windows I am testing it in Edge, Chrome and FF. Edge and Chrome show close numbers (#1 fastest). FF shows #3 is faster - same problem as Safari I think.