Your (it is your own, is it not?) translation is:
"KDDI want to use this service in various companies and department stores."
Before getting to the main part of your question, I must first say that you are not reading the grammar structure of this sentence correctly. To me, this is far more important than the main part of your question.
This is not about a service that KDDI wants to use. Rather, it is a service that KDDI offers.
It says 「（KDDIは）利用してほしい」 and not 「（KDDIは）利用したい」. The difference is huge. Are you following me?
Who does KDDI want to use the service? It is the people at いろいろな会社のビルやデパートなど.
Moving on to your question... Your question actually is a good one.
Adding 「と考えています」 at the end is necessary. That is because ending this sentence with 「ほしいです」 would make KDDI sound really greedy, unrefined, too straightforward, etc. 「考えています」 helps reduce all that in nuance; It balances things out nicely. It does not matter if "thinking" is already included in "wanting".
You will frequently see/hear sentences ending in:
Being indirect is a key to well-spoken/written Japanese. (It only makes direct translation somewhat difficult as a drawback.)
「考えています」 could simply be ignored in the translation. You could just say "KDDI would like ~~ to use this service." without using "is thinking" or "thinks".