The starting pointWhy people look for something other than Romi
The first reason is the model. Romi runs on a subscription: a seven-day free trial, then €4.99 a month or €39.99 a year. There's no permanent free plan, and the subscription requires an account. Paying a few euros a month doesn't bother everyone, but to organize meals, a lot of people feel it should be free.
The second is how visible it is what you're buying. Romi's public site describes its service in one sentence, “Romi prépare tes repas de la semaine et ta liste de courses selon ton budget et tes préférences” (Romi preps your weekly meals and your grocery list based on your budget and preferences), and details neither the grocery list sorting, nor diets, nor the number of people. You might want to know exactly what a tool does before trusting it with your weeks.
The third is about the publisher, and you can read it in its privacy policy: the company is based in the Ajman Free Zone, in the United Arab Emirates, even though the database is announced in the European Union. That's not a problem for anyone in itself, it's a criterion some people look at and others don't.
What makes people hesitate to leave: the service is in French, which isn't that common, and its seven-day trial ends with no charge if you cancel before it's over. An alternative that lost the language wouldn't be an improvement.