Do I need to keep apps on my Mac with iCloud
As Adam has said, you should disable syncing applications and yes it is safe.

However if an app gets pulled from the App Store by Apple, which you have purchased but do not have currently install on your iOS device, you will not be able to get it back from iCloud. Whereas if you have it saved on your computer in iTunes you can get the app back by syncing.

iCloud doesn't actually back up the apps on your iPhone, it only stores your data for that app, if your restore from iCloud then it will download the apps clean from the App Store and then insert your data from iCloud, so that it appears that the entire app has been backed up. 

If they backed up the entire app, for every user of an app there would be that many copies of that app on iCloud which is hugely wasteful.

So don't delete apps that are no longer on the app store else you won't be able to get them back. And if you have an app that looks like it will get pulled shortly (e.g. the app has tethering hidden inside of it) keep it on your computer. But most apps you are fine deleting and just relying on iCloud.