1. It’s cheaper. Devices can connect to 4G networks with chips that are less expensive to make because they are half-duplex and have a narrower bandwidth.
2. Long Battery Life. Devices can enter a “deep sleep” mode called Power Savings Mode (PSM) or wake up only periodically while connected. That mode is called extended discontinuous reception (eDRX). Read more on eDRX and PSM.
3. Service Costs Less. Because the maximum data rate of LTE-M devices is only about 100 kbit/s, they do not tax the 4G network as much. Carriers can offer service plans that closer to old 2G M2M pricing than 4G pricing.