There are lots of factors why VoIP is best for business:

Lower price calls per minute
Keep your business connected from any location with only a stable internet connection
Require little to no installation, in terms of software and hardware
Multiple calls at the same time such as group calls and conference
Offers more features such as caller ID, call waiting, call forwarding, call blocking, voicemail, and much more: https://www.revesoft.com/blog/mobile-voip/mobile-voip-software-simplify-your-business-communication/