-in the context of daytime VFR I suspect the mandatory installation of, and use of, a flashing light beacon would be vastly more useful and significantly less expensive.
Most aircraft already have a "flashing light beacon" and many have high intensity strobes. They don't seem to help much. The human eye just isn't good enough at spotting aircraft on a constant bearing at a range that's sufficient to do something about it.
The answer is in electronic enhancement of visual acquisition. Mode S datalinks (1090ES) provide one means for that, and already have broad adoption as a technology. Other possibilities exist, but there's a chicken-and-egg problem: such technologies are only effective if a high proportion of users are equipped with them. I'd like to see a low-power low-cost 1090ES datalink solution, but it seems to be a long time coming if the burden of the usual approvals remains.