In the warmer months putting on a pair of heavy boots can feel like a chore and it's not always necessary. For easy trails and casual walking a pair of sandals or even hiking flip flops will do the job and your feet will stay cool and comfortable. They're also great for watersports enthusiasts and climbers who need lightweight footwear that they can step into and out of easily. If you're hiking a long distance trail your main concern will naturally be the right pair of boots but carrying a pair of outdoor sandals is also a very good idea. It'll give you something to wear around the campsite and let your feet have a break from hefty boots. Open footwear will give sweaty, swollen feet the chance to breathe, cool down, and recover.
Look for a cushioned, contoured sole. This will provide more support and it'll also help minimalist flip flops stay on your feet securely. If you're going to be wandering around a busy campsite after dark or over rocky terrain, an outdoor sandal with a closed toe is a little safer than a flip flop. They're even more secure and the closed toe box will remove the chance of a painful stub.