Point-to-points (also called P2P, not to be confused with peer-to-peer) are essentially relay systems for radio waves.
Point-to-points have the advantage of creating a space in which cellular signal is quite strong, but does not create any signal itself. The disadvantage is they increase the total amount of radio “noise” in the area, which makes telecommunications projects in that place more difficult. This only really becomes an issue in certain high-traffic areas.
There are massive point-to-point stations, and smaller ones. Large relays are comparable to cell towers in size, but have much smaller power requirements and maintenance costs associated with them. Cell phone signal boosters are smaller relays, with donor antennas snatching signal from the cell towers, an amplifier designed to work with common power requirements boosting the signal, and an interior antenna rebroadcasting the signal within a confined space.