Don't ask some stranger if you should buy. Ask your wife. Have her try the functionality in Google Drive (formerly Google Docs) web documents and spreadsheets to see if they have the functionality she needs. After she's gone for a test [Google] drive, ask her if you should buy one for her.
Both a word processor and spreadsheet are functionalities of Google drive. I haven't received my Chromebook yet, but I currently use both the word processor and spreadsheets through my Google drive portion of my Google accounts.