Short answer: advertising for the short term, search visibility for the long term — and in practice both, in a shifting ratio.
They serve different purposes. Advertisements deliver traffic tomorrow and stop the day you turn off the tap. Search visibility takes months before anything happens and then largely remains in place. Therefore, weighing one against the other is the wrong question.
The distribution that usually works:
- First few months: the focus is on advertisements to bridge the period while organic positions are still growing. At the same time, SEO work begins, as it needs those months to develop.
- After about six months: the first organic positions start coming in, and the advertising budget can be reduced for the keywords where you are beginning to rank yourself.
- Thereafter: use advertisements specifically for what is difficult to win organically, or for campaigns and peak moments.
What you want to avoid is only advertising for years. In that case, you are renting traffic without ever building anything, and every euro you do not spend immediately results in one less visitor.