Further dilution on rentals probably, IF BSNL allows colocation of other operator kit. Which is a low probability event as Jio/airtel do their own tower biz. It only gives Vi more leverage over Indus as it can plead with the GOI to colocate with BSNL if Indus asks for payments on time. GOI has already invested in Vi and might be receptive to the idea and besides might make some money out of it.
From the news, Vi owes money to Indus for rentals and are late in paying.