The question you referred to in yours gives more usage notes on when you should use the "-wise" suffix, but not so much in terms of what it means. In this case, "wise" is supposed to serve as a suffix which means:

with reference to: profitwise ; businesswise

The example you quoted would be less ambiguous if they had used "computation-wise". That is, the sentence is saying that:

Floor is obscenely expensive [in terms of] computation

or,

Floor is obscenely expensive computationally

The question you referred to in yours gives more usage notes on when you should use the "-wise" suffix, but not so much in terms of what it means. In this case, "wise" is supposed to serve as a suffix which means:

with reference to: profitwise ; businesswise

The example you quoted would be less ambiguous if they had used "computation-wise". (Computational-wise seems ungrammatical to me). That is, the sentence is saying that:

Floor is obscenely expensive [in terms of] computation

or,

Floor is obscenely expensive computationally