Definitely worth it IMO for two reasons:
(1) daugher is under 10
(2) neither of you eat a lot
This is a great opportunity to get almost all of your meals covered for just $49 per day. Plan to share meals! As long as you only order one meal at a time, your daughter's credits can be used for an adult meal.
Let's assume you're traveling for 5 nights/6 days (just an arbitrary number since you didn't specify). You'll have 10TS and 10CS to cover six days of meals.
You'll have 15-18 meals during that time (depending on how many meals you'll be around for on the first and last days of the trip). In a worst case scenario, you'd need to cover 18 meals. This leaves 2 credits leftover to use at buffet-style (character) meals where sharing isn't allowed. If you need less than 18 meals, then you can add in more buffet-style meals and still have all meals covered.
Obviously there are a ton of ways you can work out your sharing, but it should be pretty easy for the two of you to cover three meals a day (including the day you check out) without having to pay for anything OOP.
Another way you might be able to "cover" a meal without using credits is to try to use snack credits for breakfast at the resort. Some cashiers will allow you to get a muffin or pastry with a snack credit. You can also use them for fruit.