Referring to Cavendish Square Holding BV v Talal El Makdessi (Rev 3) [2015] UKSC 67, this website alleges (The judgment itself doesn't reveal this):
Moloney did however allow the decision to be appealed and arranged for the case to be fast tracked to the Court of Appeal. Of the two defendents, Barry Beavis decided to appeal, Wardley settled. ParkingEye agreed to waive their legal costs allowing Beavis to appeal without fear of huge costs should he lose. [I bolded.] Sa’ad Hossain QC agreed to represent Beavis the case on a pro-bono basis.
In Delta Air Lines Inc. v. Lukács, 2018 SCC 2, Abella J. wrote:
[67] I would allow the appeal and restore the Agency’s decision. Delta is not seeking costs.
In both cases, waiving their legal costs disadvantages the (corporate) appellants, because legal costs can deter a litigant. So why disadvantage themselves? Please see the question in title.