My thought on this is that it's a lot easier for me to manage my fuel when I get assigned a hold with a firm EFC time. Especially when on min fuel. The zig zag vectors are indefinite in duration, and make it very difficult to formulate a bingo fuel plan as for when to divert.

Of all the times I've landed with "uncomfortable" fuel levels, it's been with surprise vectors, never a hold. When I hold, I compute my bingo, then head to the alternate when I hit it.