The distinction is that "acquire" means controlling interest. Investing $497 million when the valuation is over $1 billion means... (doing the math) ... Tencent has less than 50% ownership. At this point, Tencent only has an investment and not a controlling interest. Therefore, Tencent did not acquire Scalapay (yet).
This isn't being pedantic about semantics. Instead, it's being very clear about who controls Scalapay based on how much ownership percentage was purchased.
Another example of the difference... in 1997 when Microsoft invested $150 million in Apple, it did not purchase enough ownership % to consider it an acquisition. The $150m is a lot of money but MS didn't acquire Apple with that transaction. (https://www.google.com/search?q=microsoft+invests+%24150+mil...)
EDIT reply to: >Valuation has nothing to do with controlling interest. They are unrelated.
Setting aside a multi-class stock arrangement with 10x voting rights which would be unusual for non-public company at this early stage because it requires approval by the previous investors & founders, the post-money valuation is mathematically related to the ownership percentage purchased -- and therefore determines if there's a controlling interest.