That's the way I see it, too.
In addition to purchasing Steem Power, corporations may rent it. Frankly, I find it stupid to resent corporations taking an interest in services using Steem the blockchain if one simultaneously wants STEEM the cryptocurrency to have actual monetary value. At this time, the value of STEEM is entirely speculative. It is based wholly on expected future value. Practically nothing outside the ecosystem can be bought with STEEM, yet. If STEEM is to ever have much intrinsic value, it is has to be based on promotion or advertising of one type or another.
Actually, I hadn't considered that corporations could purchase advertisements.