Sure. But I would not say it is the first thing should do.
To prevent your site from getting hacked, start with the following:
- Do not use Admin as your username
- Use a difficult password.
- Use two-factor authentication
- Install a security plugin, like iThemes.
- Rename your login page to something else then wp-login.php or admin (use iThemes to do this)
- Backup your site to another server or cloudserver on a daily basis.
If that’s all done, then your next step would be to buy an SSL certificate.
On the other hand, if you need visitors to send private information over the web to your site, or vice versa, it is very important to encrypt all your data with SSL. A webshop is an example of a situation where where I would strongly recommend SSL.
Another reason to use SSL nowadays is SEO: Google has announced that websites with SSL wil rank better.