The idea behind the final cards in each pronunciation trainer isn't really to help teach you vocabulary. Vocabulary is much better learned when you're picking your own images. Those additional words are there to give you more practice with the spelling rules, so you can become more comfortable with them before you head into picking out and learning your own vocabulary.
For those extra words, the most important card among the three card models is the “What’s the spelling?” card. We've definitely had folks suspend the other two card models, which is a totally viable thing to do.
To suspend those spelling cards, go to the browser, select that card model on the left side (similar to “2". Picture Words). You’ll see something like “mid:1366716141610” in the search field.
Next, add “card:3” to the search field, and it will give you a list of only the spelling cards. (You should see “Spelling?” in the “Card” column in the browser.) Select all those cards (you can shift-click to select a bunch of them in a row) and click “Suspend” up top. You can tell they’re suspended successfully when the number in the “Due” field goes into parentheses. (from “197” not suspended., to “(197)” suspended.)