Maybe these few lines will explain why Geezer Butler is involved in this sort of a band. Taken from the following link.
http://www.epinions.com/content_109115117188
"Geezer Butler had returned from doing side projects to Black Sabbath and he brought with him many new ideas. His vision for the band was to take stock of the modern heavy metal scene and to take it in new directions.
The idea was to take Sabbath back to the cutting edge of metal by using the modern bands as a starting point. But Butler did not want to simply copy the current bands, he wanted to build new material based on the 90’s idiom.
Specifically, new metal in the mid 90s was bottom heavy, with grinding guitar riffs that were simple but powerful, guitar solos were sparse and songs without a solo were common. Vocals were gravely shouts with words not really articulated. Lyrically nobody wanted to hear the old “dungeons and dragons” stuff nor did they want the same old bombastic party rock that the late 80’s hair bands had spewed. These ideas were to be the launching pad for new Black Sabbath material. By taking strong doses of these new ideas and mixing them with the old methods and sounds of Black Sabbath, a whole new sound was to be created which would be different from the herd.
Geezer had introduced these ideas during the making of the Dehumanizer album with Ronnie Dio. But with Dio in the band he was only able to add a dash of new ideas and to freshen the old methods. The result was still outstanding despite the limiting factors imposed by the rest of the band. With Dio gone, Butler wanted to take things further. In fact, Dehumanizer had done well because it sounded like the classic Black Sabbath that the fans had been waiting for. Without Dio or Ozzy, a new audience had to be reached because the old fans had already shown that they didn’t want Sabbath retreads.
Where Dehumanizer was an update to the old Sabbath sound, Cross Purposes was a change in direction. Instead of going on with the Dehumanizer line up which offered the chance to reconquer lost ground, the direction of Cross Purposes promised the conquest of new territory with a new sound that nobody else had tried.
To an extent Butler’s new ideas worked on this album although its clear that he did not entirely get his way.
The counter point to his new ideas came from Tony Iommi who realized that metal had changed but not all for the better. Iommi seemed convinced that Sabbath could tip their hat at the new style but follow their old formula as they had done so well on Dehumanizer. Tony seemed to think that high quality “orthodox” heavy metal would win over fans. Iommi did not want as drastic a change as Butler did and its evident on the album that there is a tug of war going on between new and old ideas.
On this album Iommis guitar riffs are mostly all low register grinders. They are short and repetitive like stuff you would expect from Rob Zombie or Helmet. They all drone and pound with heaviness. Like wise his solos are short duration and very fast. On a couple of tracks it’s obvious that a solo was added because it was obligatory to the old format. Although there are some that don’t have a solo at all.
Iommi seems to be taking Butlers advice to an extent on this album. He seems to realize that the eighties are gone and new sounds are needed. He does not wholeheartedly embrace the change but he sounds more cutting edge on this album than he did on Dehumanizer."