A key difference between SNMP and streaming telemetry is the method of data collection.
SNMP polls network devices to collect information or set configuration properties. The approach, while generally reliable, can also lead to delays as long as five to 10 minutes before information is received from a device veritable eons in today's networks. Streaming telemetry flips and streamlines the process. Instead of the pull model used by SNMP, streaming telemetry uses a push model to continuously stream data from network devices to one or more network monitoring systems.
Reference:
https://www.networkworld.com/article/3575837/streaming-telemetry-gains-interest-as-snmp- reliance-fades.html