I was using outdoor decking oil on my teak hatches, dorade boxes and strakes. I found they were quite okay. The only difference was that they do have some ferric oxide in them for UV protection, which does leave a slightly orange tinge. This 'tinge' also marks paint
unless it is removed immediately after being spilled, splashed or otherwise comes into contact with non timber surfaces. I think in terms of durability, exterior decking oil is better than marine
teak oil. It is much less expensive, but the orange thing may deter you.
I guess outdoor teak oil may also contain ferric oxide, but a quick look at the ingredients will tell you that. The only other thing I would be concerned about is if the non marine
product contains any varnish
. If it does, there is the problem of whether it needs to be removed or abraded prior to recoating.
I found that oils lasted about three months before needing a recoat. But, that boat was kept in Darwin, northern Australia
, where the sub equatorial sun is relentless all year round.