But, Amateurish. Perhaps they dont want to bother doing washing on holiday, and depending when they're going, and what part of France they're going to, they might need to account for different types of weather, clothes wise.
You could just take the clothes you're standing up in and wash them all every night, but it's a bit miserable to do so.
If the OP thinks she will save a lot of stress and bother by taking one hold case, then she should do so.
Most people on this thread seem to be light packers, but I've seen people on here who insist that they need a new daytime and nighttime outfit every single day, plus sleeping/lounging clothes, several pair so f shoes, multiple ipad type devices, swimming kit, piles or different types of towels, hair dryers, straighteners, sacks of toiletries, cosmetics and medications, certain toys and blankets for the DCs, specific types of food not available abroad, and a hundred other things I haven't thought of.
The OP doesn't sound like one of these people BTW, but just because some people are happy to wear the same clothes multiple times and do washing on holiday, it doesn't mean that others who don't want to do this are being ridiculous.
I also think that the OPs DH will be wanting to put some of his stuff in other cases - she mentioned electrical items, but he doesn't appear to be taking any spare shorts/trousers or shoes, which is never sensible and I bet he hasn't thought about toiletries and medication either.
Things like paracetamol are often much more expensive abroad and only available from pharmacies, which are usually closed between Saturday lunchtime and Monday morning. I therefore think it is sensible to take things like this with you.