The main cases to use SBR:
You have Heavies.
Do you build anything EXCEPT bombers if you have heavy’s???
Let’s be honest, Heavy Bombers are so powerful that it is an almost assured game victory for whichever side gets them. And I have never seen a game last long enough after one side gets heavy’s for the other side to also get them.
Your opponent has (1) low income, but a (2) ton of defensive units holed up in the capital, and (3) your seige forces are not sufficient to win the capital battle.
Combining SBR and the trading of territories next to your opponents capital will allow the build-up of your seige forces to gain the eventual edge. By then, your income should be several times higher than the opponent you are about to kill off.
I still like using SBR’s to PREVENT my target from building up massive defensive forces. That is why as Japan I bomb Russia every chance I get… each run means less INF in Moscow upon my force’s arrival.
Of course it could also be that I just HATE siege warfare. I’ll press a battle against a strong oponent just to weaken those forces if I feel I can re-build faster than he can; rather than wait for me to build to overwhelm. That way, if one of my allies gets to a position to ALSO be able to strike, they face a weaker target. And if my allies don;t get a chance to strike, my nation that made the original suicide run will still be outbuilding the target and can move more forces in and take it anyway. Now, I have to be able to last long enough to do SOME damage… I won;t attack with a fighter and 3 INF against 30 INF. But give me 7 INF, a couple of tanks, and several fighters on 30 INF, and I’ll blast in, inflict damage, and retreat; then do it all again as more cannon fodder arrives at the front.
Lather. Rinse. Repeat.