There are no top Cubans anymore. So it's a moot point.
As far as LA prospects, there are only a few each year that are "top," and even a lot of those flop. Top 20 or 30 in LA is pretty nebulous, you're projecting 16 (actually, when many of the deals are negotiated, 15) year old players. So I don't really get excited if we sign 4 in the top 30 or top 50, I suspect there's a rat's hair of difference between #30 and #50.
So it's not a matter of "saving" money, rather, given a limited amount of funds (even trading for allocations), an inefficient market where most of the top 20 are overpriced (because most teams don't invest heavily in LA scouting, so the top tier are better known, not necessarily better prospects), spreading the money around makes sense.
One reason I applaud the recent expansion of the international scouting group is that there's a market inefficiency in information begging to be exploited.
It's much harder to find a "hidden" American prospect given the saturation and availability of videos of practically any HS or college team.