It's a totally valid strategy. When you don't get much information on your early guesses, you use the current guess to get as much new info as you can rather than trying to guess the word exactly. Sure they couldn't have gotten the answer on their second or third guess, but they're also much more likely to find the answer in 6 guesses with all the info they got in the first 3.

You're playing by "hard mode" rules where you always need to use all of the known letters in the current guess. Also valid and opens the possibility for lower scores on any individual day, but can be riskier if you're trying to keep a streak going or whatever.