Bombardment attack?

[miljkovics]

I wonder what is a reason behind not having possibility just to do bombardment (by artillery) attacks?
It would be logical one could do only bombardment while doing long siege of city fort(s), which can provide insanely combat bonus rendering any deliberate attack against it to effectively suicide (banzai) attack.

So far, only useful strategy against heavily fortified city forts (Odessa, Sevastopol, Leningrad and about to see if it applies to Moscow too) I could find was to bomb railyards and ports to 100%, and then bomb units until defender collapse. That can take a lot of time with heavy bomber losses...
Which make me question what is use of that super heavy and siege artillery units if only way to use it is as support barrage to actual infantry/tank attacks?

[AlbertN]

Taking a wild guess but:

A) Bundled in attrition losses for being adjacent. - This may be far fetched.
B) The Soviets will perform artillery bombardment all the time on the Germans or so, with their bazillion of guns, across all the line.
C) Too situational to be truly coded at lenght if it is only for few City 'Sieges'.