His vehicle may not need it. But my Jaguar F-Type certainly does. The direct injectors tend to fail by sticking, due to varnish and carbon. The regular use of Techron or SI-1 solves the problem.At the end of the day, your car doesn't need Top Tier fuel nor any aftermarket fuel additives/cleaners. Don't overthink this.
The thing is, the Jag's injectors are expensive, and very difficult and time consuming to change, often requiring a special, brutal, tool to extract them from the cylinder heads. So the SI-1 is worth every penny.