Criminals are often opportunistic and will go for the easiest option. They don’t want to get caught, after all, so it’s easiest that they find the most foolproof option when breaking and entering, and finding items that it is worth them stealing. This means that if you give the appearance of a highly secure building, it is less likely to attract criminals who are looking to steal something quickly.
That’s not to say that you don’t need actual decent security measures as well. If you have security measures that quite obviously don’t live up to expectations, then you won’t do yourself any favours. However, it could be a measure as simple as fitting a new garage or warehouse door, which will provide a sturdier barrier but will deter criminals visually as well. Choose a Secured By Design option if possible, as this means the design has been tested by security professionals.