Uptime and personal preference. If your node is down your zaps will fail. I’ve done it both ways and found using nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm custodially to be faster and very reliable but I always sweep my sats to my node when I have more than $10 worth of sats.