It's totally up to you. Both ways are good, they're just different
When you add Sellvia products from
Sellvia catalog, you have to manually choose and add each product, which can be time consuming. On the other hand, when you add ready Sellvia products packs you save a lot of time since everything's already there. Also all the packs are curated by professionals so every product there is surely in trend and going to sell well.
Personally I prefer the second way of adding Sellvia products, it's much more easier than spend hours choosing nice product from the catalog. Also often Sellvia launches new product packs for some big events and holidays, which is also really convenient. Good luck with you Sellvia store!