I think its more of a quality of life change more than a buff, they probably know hes one of the most picked controllers and probably did it because sometimes picking up spike and insta cancelling ult didnt work.
Pretty much. When making this change it was a discussion around:
"should we remove Omen's ability to pick up the spike with ultimate???" and I didn't really feel like that change was necessary as Omen's ult is pretty fair and niche anyways. It felt like a bug how you had to cancel the ability to do the thing you were intending to use the ability for in the first place.