^Armed nukes in a warzone. Pretty much any that is mounted to a pylon or loaded into a bomb bay is armed and ready to go. This is also in the 60s when munitions were still primitive and electronics are not at where they are today. There simply is no way to turn the bombs on or off from the crew compartment. The USSR also had a habit of stockpiling weapons. If need be they could dust off some tanks and artillery guns from WW2 and send them out to go fight.
West Germany was essential a buffer zone. You're the commander, are you going to waste your precious fancy bombs on West Germany, or are you going to save them for the United States, France, and UK who pretty much run NATO? Why use those when you can go waste those old rusty nukes from early 1950 something.
USSR also had missiles of all shapes and sizes, and ranges. The SCUD for example had some form of guidance, but it was primative and only reserved for targets like Airfields and military bases. However again it was Primative. You had the Luna(NATO name Frog-7) which was basically a modern day V-2 with a nuclear warhead. You know the enemy has airfields that have planes which are threat your mechanized offensive, you can use those missiles. However you really wanted to know if you killed a base you use a bomber which comes with the risk of getting intercepted and shot down by either planes or grounded based AA. Plus you are dropping smaller yield nukes, so you know you aren't wiping more than what is needed.
There were also non nuclear alternatives like the BM-24 which was a MLRS system that fired some 12 primitive 240mm rockets, However there was no guaranteed chance to hit. You also had the BM-21 that had a wide range of muntions from high explosive, cluster, chemical, and minelets. However again those don't cause as much damage as a small nuke would.
Which brings us to the SU-22. It's a medium bomber super sonic jet bomber from 1962(SU-22M is a different plane) which means its pretty much good for destroying stuff that is really close by. It's fast which means it can get in and out. Might not be SR-71 fast, however there is a chance it could escape.
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