When using a team site (wiki type functionality) and editing the page you may notice that the Spell Checker isn’t available.
If you are running SharePoint Standard or Enterprise Edition then you have the option to enable this by turning on the Site Collection Level SharePoint Server Publishing Infrastructure feature.
This provides a number of additional features in addition to the Spell Checker, if you want a deep technical understanding Mirjam has a good post on this.
Activating this feature turns on Spell Check.
The question is should you do this just for Spelling?
I couldn’t think of any reason so I asked the MVP community and the general consensus was this should be fine, just be aware of the additional things it makes available like permission groups, additional features and web parts.