For larger systems, and for systems where security is critical for things like being compliant to vertical regulatory needs, your current internet connection might not be adequate. The internet doesn't do quality of service (QoS), and bandwidth can be unpredictable. Network congestion can ruin a conference call, and activities such as DNS hijacking can put your business and data at risk.
Grasshopper makes it easy for companies to receive calls on the mobile devices they already own. Features included in Grasshopper’s plans include extensions, call forwarding, voicemail-to-text — each without the need for investments in expensive hardware.

In practice, most businesses are simply handling this on a case-by-case basis since COVID is a temporary problem. Most home networks can handle the extra load as long as the employee makes sure that other latency-sensitive traffic, like gaming or video streaming, is kept to a minimum during the hours when they need to talk. If some home routers develop problems, IT staff simply build a queue and handle those one at a time. Sometimes they'll be able to access the router remotely with the employee's permission, sometimes they'll have to walk that employee through configuration steps to fix the problem. Sometimes the employee will just have to live with it unless the company springs for a new router or a higher bandwidth tier from the employee's ISP.
If your company is using a cloud-based VoIP service like Nextiva, Ring Central or 8x8, let me know when you send your script so I can create the correct audio file to use.