The starting life total bit is clearly intended to make it not break Commander - where you start at 40 life in a multi-player setting) In Constructed, White Weenie was needing a card like Path of Bravery for awhile. The first half of this card already makes this card a variant of Honor of the Pure, but one that doesn’t restrict itself to white creatures. But the second half of this card is what makes it so powerful. Having lots of little creatures consistently gaining you life not only keeps you in the game, but it makes it pretty much impossible for burn decks to race you.
The best part of Path of Bravery is that it costs 2 colorless and a White mana. This means that it’s easy to splash in green-white, red-white, or blue-white creature-based decks. With Soulmender and Fiendslayer Paladin already a part of Magic 2014, plus creatures with Extort from Gatecrash, life-gain was suddenly looking like a valid mechanic again!
Despite this being a darn good card, it saw fairly limited play in Standard. You’d find three copies of Path of Bravery in the occasional White Weenie deck. It was also a pretty strong card in Limited, especially at Grand Prix Prague 2013. The deck that Path of Bravery most shined in was Martyr Life in Modern, a variant of Martyr Proc. Like the older Soul Sisters decks before it, it relied on Soul Warden, Soul’s Attendant, and Spectral Procession to flood the board with a bunch of creatures. It was called Martyr Life due to playing Martyr of Sands, which could gain you a ton of life, plus the one copy of Path of Bravery in the main deck and one copy of Chalice of Life in the sideboard This was actually a fairly successful deck from 2013 well into 2014.
Since late 2014, Path of Bravery pretty much disappeared from competitive play, but not from play entirely. It still sees a fair amount of play in Commander across a wide variety of decks, including Darien, King of Kjeldor, Karlov of the Ghost Council, Oloro, Ageless Ascetic, and other decks with either a weenie creature or lifegain theme. While Path of Bravery isn’t quite as good in Commander due to having to stay over 40 life, it’s still a solid Enchantment.
Could Path of Bravery re-emerge in Modern someday? It’s certainly possible. As a card that did have its day in the competitive spotlight, you never know.