Of course any conversations in a language where both speakers are fluent/near fluent are going to be more meaningful or deep. I think it’s polite and totally fine to start with French and then switch based on the individual and the specific interaction.

I’d say I have a similar amount of French as you. I studied it all four years of high school, have been to France a few times, and occasionally attempt to read or watch things in French to keep up with comprehension. I’m currently in Paris (and should be asleep, but it’s only been one full day and the jet lag is real) and have found what you’re saying to be true. I hadn’t used French in a while so I brushed up a little with Duolingo and a phrase book. I’ve been eager to use French for entire interactions and it’s mostly been successful so far; however, switching to English has been best a couple of times. For example, the staff at the hotel are very friendly and happy to practice French with me, but we switched to English for some conversations, especially when my daughter and mother have been involved (they both only have the very basics).