Yes it can – provided the water source is a limited volume reservoir, like a vase or a pail. The water level in the water source must be about 8″ or more higher than the end of the tube that drips into the plant so that gravity can do its magic. It is simple to set up a siphon from that water source by sucking the water through, and then placing the tube through the Plant Booster device as you would for setting up any planter.
The maximum drip rate will be much slower than when the water is supplied by house pressure, but when a plant has 24/7 to get its water as and when it needs it, there is no hurry.
When located in a house which is kept at a comfortable temperature, house plants typically do not consume as much water as plants outside in the heat. You can experiment and pick a volume which lasts long enough for you and work from there to arrange a volume sufficient to water your plants while you are off on that well deserved holiday.
It must be noted, however, that when connected to an always on outdoor water source, like the garden tap, the Plant Booster system is intended for outdoor use because the barbed fittings are not considered appropriate for indoor use. The water is supposed to always be on to get the most benefit from the way the system works. If for whatever reason a plant is moved off its device, or a tube was to come off a fitting, for however long you are away water would continue to flow onto the floor of your house, which is probably not a great idea.
When house plants are being fed from a limited volume by gravity, the risk of water spillage is thereby reduced to whatever level you are comfortable with.