To be perfectly honest; other than entering text or making the occassional change to some text, I can't recommend doing much of anything (formatting-wise) in Book View.
If you don't care about the code "behind the scenes," then there's little harm in doing some bolding, italics, or alignment/spacing stuff obviously. But splitting/merging and all Find and Replace needs to happen in Code View (as does the application of saved "clips").
I honestly don't know the details of why the spellcheking feature has to be done in Code View. But suffice to say that if it was easy to make the spelllchecking feature available in Book View, it would already BE available. It's not an unreasonable (or uncommon) request by any means.
You'd do well to learn to "see the text" in Code View if you can (even if you don't want to mess with html). The more you learn about editing epubs (even for casual, personal use), the more you'll realize that doing so without digging into the html/css a bit isn't very feasible.