I doubt Sedo is purposely holding money for that reason. I say that because the extra cost of customer support dealing with complaints / loss of goodwill / less listings / more chances of deals falling-through likely exceeds any interest Sedo would earn on the float.
Furthermore, the bank accounts wires are being directed to might not even be interest bearing accounts...
But even if they are, how much would Sedo realistically earn by holding funds an extra few days... probably very little; not worth the hassles / upsetting customers.
Ie. $10,000,000 cumulative annual float x 1% apy = $100,000
That sounds pretty good, but even 1% annual percentage yield (apy) interest accounts are rare these days, and hence the above scenario is overly optimistic ... likely off by an order of magnitude for both that reason and that the cumulative annual float (which would be far less than total annual sales), even if Sedo does play that, is likely way less than $10,000,000...
The reality is the amount of earnings from playing such a float would likely be a lowish 5-figure number at best... imho, unless Sedo is moving billions per year, like financial institutions routinely do, playing the float doesn't seem worth the bother.
If Sedo is purposely holding funds to earn say an extra $10K or so per year, Sedo is penny wise and pound foolish, since the extra cost of customer support dealing with complaints, combined with loss of goodwill / less sales transactions likely far exceeds that.
Ron