It is a question of symbol, of common life and of resources. On the resources side, if being in a group is a definite advantage, being in several allows you to receive more resources, to have a greater right to draw on control tools (commissions of inquiry), to have more of staff.
If all this were pooled, there would be less for the whole Nupes than if they were autonomous, and we would also have to agree on the distribution in this large entity. Hence the idea of an “intergroup”, mentioned during the campaign, a coordination mechanism which does not exist in the Assembly’s rules of procedure, but which would allow these groups to be united while remaining autonomous .
However, there is also the symbol, that of forming the first opposition group, which for a few seats escapes La France insoumise. This would reverse this trend.
Recently, we heard that the presidency of the finance committee or the first vice-presidency could escape the Nupes and go to the National Rally for this reason. This would only be possible if the presidential majority broke tradition, and took part in this vote, which would be a small revolution compared to practice. Normally, on these positions, the majority must abstain.