Burns is a hedge with upside. Nothing wrong with the contract or the player. If Browns breaks out in camp then give him the job. If Jones gets injured then Burns is there. 2 million to maybe be a backup? Not horrible.
Lack of serviceable DB depth in SB has cost Seattle TWO Superb Owls. So this is probably what Pete is thinking.
1) SBXL, we lost S Marquand Manuel in 1st half, and his replacement was man-off-the-street Etric Pruitt. Stealers noticed and took advantage in 2nd half.
2) SBXLIX, we lost Jeremy Lane to broken arm + ACL, on his return of picking off Brady in EZ. Insert Tharald "Toast" Simon and Patriots target him repeatedly FTW.
If Burns can be serviceable CB depth when starter(s) go down, it's a win to have an actual NFL-level replacement to plug in, and for $2M. Maybe even blossom in Seattle into starter quality, a Byron Maxwell in reverse? (Maxwell starred in Seattle, sucked for other teams after he left) Coaching up DBs is Pete's specialty, it's what he played in college. Well, with Tre Flowers, not so much.