I would prefer a land hit to an abduct if I'm hitting for any sort of reasonable goal rather than just hitting to hit. Learn attacks were already questionable when they took 8% of books, why would they be better at 2-3% of science.
Because science is so luck-based it's hard to build a strategy around it, and a whole lot better to play for acres or war/honor... save the troops and time spent abducting and put that towards generating money and hitting targets that will war (or failing that, donate acres and honor).