Scientist: Well, it's better than the above, but still bad for the same reason that abilities are too abundant to justify spending talents on.
Scientist is worth a varying amount of ability points; it adds 1 to your current ability level, and going from Repair 4 to Repair 5 costs 5 points, so if you buy Repair 4 and Crafting 4 with actual points, the extra boost from Scientist is (at that point) worth 10 ability points, as it will take you to Repair / Crafting 5.
Only useful if you intend to actually buy Repair and/or Crafting up to a highish level, but the more you invest the more points it becomes worth overall.
The same goes for Politician; if you buy Charisma 3, the bonus 2 from Politician are worth 9 points, for the downside of losing 1 attribute point.
Situational, yes (definitely don't get them at all if you don't intend to invest further in those abilities for that character), but in certain cases it can look like a solid use for a talent slot or 2, freeing up to 19 ability points to use elsewhere
