Is it safe to store oils, vinegars and other sauces in reused gourmet oil tins?
If the key issue is safety, I imagine the cans of the type you indicate are probably as safe as any others, assuming that you can clean them adequately.  Those corners at the top are out of the reach of a bottle brush.  They will have a lining to prevent them from being overly reactive.

Still, I would not use them as they are going to be very difficult to clean, and you cannot monitor the contents.

I would recommend getting an oil dispenser specifically for the purpose, such as this type:


They will let you see inside, and make it easy and clean to pour.  With a funnel, you should be able to fill them easily, and they don't have corners (at the top) out of reach of a bottle brush, making them easier to clean.

Still, this type of dispenser is not meant for long term or bulk storage, as many oils and condiments should not be exposed to light and air (although the dispenser minimizes air exposure, especially when it is below the fill line).  You would use them for working amounts that you would consume in a couple of weeks.

The containers tend to be made of glass, which you know is non-reactive.