I believe .24 and .5 are withing the margin of error for stats when you need 2 point difference to have a meaningful game effect.
For any one score, sure, but the cumulative effect is about 1.5 as I wrote depending on which methods you are comparing, and 1.5 is nearly the 2 you need for a +1 modifier. So, while the differences are not necessarily enough to make one system better to another, they can be used as such.
For example, the standard array is 15, 14, 13, 12, 10, 8 or +2, +2, +1, +1, and -1, for a total of +5 modifiers. Point buy can give you 14, 12, 12, 12, 12, 12, for a total modifier sum of +7, which is +2 greater than the standard array. Even the accepted standard array equivalent for 4d6-L is 16, 14, 13, 12, 10, 9, totaling +6 in modifiers.
Thus, point-buy can give you +7, the "standard array" of 4d6-L gives you +6, and the standard array is +5. Each system can show a +1 total modifier better than the other. Is the difference meaningful? That is up the the individual to surmise, but the systems are not really equivalent. I would never use the standard array, for example, if point-buy was an option.