Yes po. Safe naman. I have a lots of pics and vids sa Google Drive. But it's better you maintain highest possible security of it like access only using sms verification codes.
Depende sa idea mo ng "private". Kung delikado 'yan (R18+) or sobrang confidential, it's better to store your files somewhere else. Kailangan mo rin i-consider yung possibility na baka ma-häçk ka.
Kung private files lng, safe sya. Dahil wala silang rights na ma view ang files mo, unless na share mo or na public. Kung naka Gsuite or Shared drive wala na privacy, dahil may rights ang owner/admin.
Pwede naman yan, basta hindi shared yung folder. Dagdagan modin security nang Google account mo para panatag ka na di mahahäçk, for example sms verification at 2-step verification para safe talaga yung account mo at google drive.