Every hire is a gamble and I'm sure OU wished BV had head coaching experience but rarely you get everything you want and even when you do sometimes it still doesn't work out. This is really as safe of a hire as they could get.
Hiring Venables is as safe as they can get? I think it is a good hire, but that says a lot about OU's status as an elite program. Bama is hiring Saban. LSU went with Kelly, who is a perfect fit for the SEC scum/win at all cost crowd. USC got Riley. Now those are about as safe as you can get. They get a guy, for various reasons, they did not go with when they decided to groom Riley.
This is more like UT pulling Sark as a fake blueblood imo. Regarded as one of the brightest offensive minds in college football, a ton of positive PR coming out of Bama. In Sark's case, there was more "known" given his record at USC and UW, so in some ways more safe.
And no, I would not have said Day or Smart were as safe as it gets, although they seemed like good hires from afar (Day more so than Smart, a DC from Bama seems risky to me).