I largely agree with Kweassa. Losing the manpower along the front actually costs the war effort however a single person working strats can be helpful at times.
I'll sometimes run an Osti out to a strat. I can take out ~60% of any strat target with an Osti. To do so it obviously has to be close to a friendly base and, being so is usually already down to, or under 60% already. This means I can go in alone and bring it to 0%.
The loss of me along the front usually has little impact to the overall war effort, but, doing this is only effective if other friendlies are working those targets at the fields and those targets are making a difference in the war effort. Without those two conditions being met my time is wasted so these instances have to be choosen carefully.
While some are very good at strat bombing most aren't. I rarely see a bomber take more that 15-25% of the target which makes this a marginal use of resources and those who fly attack planes to strats are simply a total waste.
In addition, with the older bigger maps there were several supply zones. Now we have one zone that supplys all fields in the arena. When attacking the strats now you also have to take into consideration the war effort between the other two countries and the ramifications of this. Are you simply helping one of the other countries win faster or might this help a losing side hold on a little longer as you make progress against the bigger country?
There's potentially a lot of balance involved in the decision to go after strat targets unless your side is already winning handily but then it's not really needed anyway.