Let have these two combinations of chainring/cog. Both for 100 rpm, have almost same speed (and we can of course find cases where the speed matches exactly, but this is a quick example).
50x19-->20.58 km/h 34x13-->20.50 km/h
My question is, (ignoring the small difference in speed in this particular example) is there any difference in these 'equivalent' combinations? Can we -on the bike, experience any difference? or is absolutely impossible to tell?