Large differences between courses
I find that there are significant differences between courses. In Spanish for English speakers, I get to speak a lot of sentences, practicing pronounciation as well as translation from Spanish. In general, the focus is on Spanish to English. In Catalan for Spanish speakers, when I make a mistake, the same sentence is repeated twice, to make sure that I learn it well. Also, there's a focus on translation from Catalan. In Czech for English speakers, there's no speaking, no practicing pronounciation. That's ok with me. But the focus seems to be on English to Czech translation. A lot of sentences appear twice, both EtoC and CtoE. But the English to Czech appears first. I rather have Czech to English first, because it's easier, then you learn what the sentence is in Czech, so a couple minutes later you get to translate it into Czech.
Then, in Spanish and Catalan, the sentences make sense. They are sentences that you would use in everyday conversation. The reason I like this is not so much the usefulness of the sentence itself, but rather, when the sentence is predictable because it's an ordinary sentence, your brain can deduct meanings of words and constructs from the rest of the sentence. Everybody learns in a different way, I learn by reading sentences and remembering words and meanings in the context of sentences. The Spanish and Catalan courses help me here, the Czech course doesn't help at all because it uses weird sentences a lot, like "I am a small blue thing". Every time I spend time thinking "is this really the correct translation? What am I doing wrong?"
For this reason, I enjoy Catalan a lot more than Czech. Which is a pity, because I'm on DL to learn Czech, not Catalan.
Fyi, I am learning Czech as a novice, I already speak Spanish, I'm just practicing it here, and I learn Catalan a little just out of curiosity, after what's happening in Catalunya right now.
Chances are those weird sentences are there to help with grammar. Catalan grammar is MUCH easier than that of Czech, meaning more practical examples can be used to teach grammar in Catalan than in Czech. Grammar is much more difficult in Czech, considering there are more aspects of grammar that one would need to learn to be proficient in Czech.