How Top-Funnel DSP drove proven incremental ROAS on both D2C and Amazon?

The context

Smartbox operates in a highly mature and saturated category across three key markets: France, Italy, and Spain. To maximize the impact of their significant media investments and unlock new sales growth, the brand needed to evolve from simply capturing existing bottom-funnel intent to proactively generating new demand.

The major challenge was to reallocate budgets toward full-funnel awareness without wasting resources.

That’s where we came in to help Smartbox answer three fundamental questions for the brand’s omnichannel acquisition strategy:

What is the true incremental impact of full-funnel campaigns on both the D2C website and the Amazon marketplace?
How can we combine the measurement data from these two different platforms?
What is the optimal path-to-conversion sequence to maximize the efficiency of Smartbox’s media investments?

The solution

To overcome this measurement challenge, we designed a full-funnel strategy that positioned Amazon DSP as our ultimate dual-impact omnichannel engine.

The principle is simple: shift from a reactive dependency on bottom-funnel searches to proactively generating net-new demand across the whole funnel, and validate every euro spent using Amazon Marketing Cloud (AMC).

The methodology was carried out in 3 key steps:

Top of Funnel (TOFU): Generating awareness early through premium CTV (Prime Video, TF1+) and Brand+ placements (Twitch, Fire TV) to build mental availability and feed the conversion funnel.
Mid & Lower Funnel: Leveraging AI via Performance+ (Acquisition, Remarketing, Retention) and Sponsored Ads to dynamically target users with the highest purchase probability.
Measurement (AMC): Conducting robust incrementality studies to observe the real variations in sales and isolate the incremental impact of the TOFU campaigns across both ecosystems.

To make sure our measurement was scientifically rigorous, we tracked the exact step-by-step journey of our buyers.

This study allowed us to prove our ‘Better Together’ hypothesis: showing that when a customer sees an upper-funnel awareness ad before a lower-funnel search ad, it massively multiplies the conversion rate compared to running search ads alone.

The results

The strategy was a success, revealing the extraordinary performance of upper-funnel Amazon DSP campaigns while paving the way for continuous omnichannel budget optimization:

13 %

incremental share directly attributable to the TOFU campaigns.

1.3

incremental ROAS

6.3 x

increase in conversion rate (CVR) when combining Sponsored Ads with DSP BOFU compared to relying on single-lever search strategies.