Many of the best chests (containing skill points) are behind Level 2 or 3 locks. Do not spend your early skill points on health upgrades. Prioritize the skill. Without it, Chest #3, #14, and #22 are impossible to open.
: These require the Lockpicking II skill to open and often contain high-tier crafting materials or unique gear. Mission-Exclusive Chests Assassin-s Creed Syndicate Jack The Ripper Chests Map