I prefer playing on one platform when playing poker, because i play the game recreationally and i'm looking to relax and enjoy. I see many substantial advantages, including:
1. Easy to set up and play. I don't have to keep track of multiple login details for each site and all of my money will be in one place.
2. I'm familiar with the Setting. If i commit to one
poker site I cam better familiariz with it's platform and enjoy a more comfortable experience.
3. I likely playing against the same players and familiarize with their style of play.
4. Loyalty bonuses are easier to claim. All poker loyalty bonuses revolve around the frequency of play. And sincer i'm playing only on PokerStars i reach the bonus requirements sooner.
Of course there are also weaknesses playing on just one platform but it is my personal choice.