Thinking I’ll try Lapua brass for my 6.5 creed , what is the deal with the small primer pockets ?

Competitive shooters prefer the small primer, contributes to accuracy with some powders.

The Lapua SR brass has worked great for me. Heads up that the flash hole on these cases is undersized too - 1.5mm (0.059"). Many decapping pins might not fit it and will swage out the holes when you deprime.
My Redding FL dies had two decapping pins and the smaller of the two did fit the holes. I like to use a Lee Universal deprimer, so I just got an extra pin for it and turned it down to fit the Lapua SR cases.
Check this out:
Lapua SR case

Good luck,
Rex

Supposedly the primer pockets hold up better with the SRP

There's more meat in the case head with the small primer pockets so they stand up to higher pressures better. The downside is that small rifle primers might have ignition problems in really cold weather with some powders, they don't have enough primer compound to give reliable ignition when it's really cold. I hunt in Mississippi so I've never had that problem, but some who hunt in extreme conditions up north have had trouble.