is a ps4 500gb enough storage if you plan to only buy physical games?

The PS4 still needs to install games to the hard drive, so you'll end up using the same amount of diskspace regardless of whether you play physical games or digital ones. That said, you can always delete a game and re-install (or download) it at a later time - this won't affect the save files so you won't lose your progress.

The PS4 will reserve part of the hard drive for its operating system so you'll have about 384GB of free space, which will be enough for 10-15 games depending on the sizes.

Considering that the PS4 must "install" games onto the storage drive before running them (as the BD-ROM drive is such a major performance bottleneck that you cannot run games directly off the disc), you will likely start running into problems when your library starts hitting the double-digits mark under the "worst case" scenario.

The 500 GB storage drive has ~450 GB's of usable space (after commercial rounding & drive formatting) & one BluRay disc can store around 50 GB's. Then there's game patches & updates, DLC & personal save files can increase the storage demands for a single game. GTA V, for example, will want around 65-70 GB's for itself. Many of the CoD games, with all the DLC can easily break the 100 GB mark (sometimes pushing 150 GB's).

If you're going for more indie, digital titles... you might be OK as indie titles tend to be much smaller in size. Otherwise, consider picking up an external storage drive (like a 1 or 2 TB drive) to supplement the PS4.

Hope this helps!

It depends on how many physical games you are thinking of.

Games on disc will be installed to the hard drive and ran the same as if you bought them digitally (unlike PS3 games that did play directly off of the disc).

So there is no change if you go physical or digital. You'll be able to store about 8-12 AAA games on the system before you have to delete things to make room for more.

I have a 2TB drive in mine with almost 200 titles in my digital library (most are small, the free games from PS+, etc.). We had to delete a few games to make room for the Call of Duty: WWII that my son bought earlier this week.

(The top 3 games in terms of storage space were all Call of Duty games with over 90 GB each due to the DLC).