Standardization.
SSIS in general has a hugh disadvantage towards tsql - it pulls the data out (unless you just send SQL to the database. It's main advantage is a lot more flexibility and actual power than SQL (plus it can run on another machine, adding scalability).
In your case it seems somoene has decided to standardize on SSIS packages, likely for standarizing - and this makes a certain amount of sense. Not saying in this case, just that standardization is a good thing in general. The rest is opinion based - so I will not talk about it here.