Target barrels don't have to be free floating. It's been the norm for many years, but not the only way. The BSA Internationals (bar the Mk III) were full-length bedded, and shot pretty well. The first Dewar 400 on the 1989 prone targets was shot with a 1950s Mk 2.

Free floating is/was popular because it isolates the barrel's firing vibrations from uneven pressure. Wood stocks were the only option when free-floating became popular. Wood can move with changes in temperature and humidity. It also has to be carefully fitted to ensure a good fit all along the barrel. Free-floating is both a precaution and a manufacturing quick step. However free-floating does put a greater load on the receiver. Hence many gunsmiths would bed under the barrel for support when epoxy bedding a wood stock.

Clamping a barrel isn't new. The EC's double clamp is derived from another French design, the Unique X-Concept. This was pretty rare over here, but won the Men's 3-P at the Sydney Olympics. The idea is to reduce the stress on the barrel, but still allow vibration. The clamps are rubber lined; the original X-Concept had sleeves, where the EC has o-rings. On both the clamps can be moved to tune the vibrations.