The point is market. Handball and Basketball are very popular in Germany, Spain, France - the biggest western european markets. Hockey is not. You need to get relativelly big tv contract/sponsorship deal for ECC, but you dont get it in Spain or France or Germany. Finland/Sweden/Czech rep are not big/important enough to generate big tv deals, especially if you dont have russian teams (big market and top hockey country + great teams).
The DEL comfortably out draws both handball and basketball in average and total attendance in Germany. Per Wikipedia generally each year there is only one German club playing in basketball's Euroleague. I can only find Internet hearsay regarding TV money, so you can choose to disregard it if you wish, but TV rights appear to be worth very little. I think you are overestimating the interest in club basketball and handball in Germany. On the surface it wouldn't appear that neither sport, at least on the club level, has a significantly higher (if any at all) level of interest than hockey.
According to any numbers I can find online France's basketball league averages about the same as hockey's EBEL or the Swedish 2nd tier. France's handball league averages even less. As with Germany, and once again just hearsay, TV rights for both sports appear to be minimal.
Club basketball in Spain does seem to be a pretty big deal. The league seems to average in and around about 7,000/per game, so a few hundred more than the top drawing hockey leagues. Handball on the other hand... Not so much. Spain also has a siginificantly smaller economy than either France or Germany. To be fair, outside of Germany, it is also far larger than any of the economies of the countries involved in the ET (or whatever they are going to be calling it).
Italy is another large country that is generally considered a European basketball hotbed but interest in club basketball seems to be closer to the levels seen in Germany and France. Handball seems to have a very low profile in the country.
Also... If hockey is so insignificant in Germany and the markets of Sweden, Switzerland, Finland, Czech Rep, are too small to gererate any meaningful revenue why is the KHL as interested in those markets as you insist they are?
With all that said, hopefully the top teams from the KHL are involved/invited. But even if they aren't hopefully the tournament will be a long term success. Not sure why anyone would root against it.