A lot of medical software has legitimate reasons for network connectivity. For example lab tests/results, GP practice software can integrate with the local providers and a doctor can order blood tests done directly to the lab and have the results sent straight to the GP practice electronically. Also support is another big one, if you are paying $10k for some software and you are having an issue it is always good to have a technician able to remote in and solve it quickly.
The answer for this sort of software is to not buy it outright but instead be paying for it yearly/quarterly. This moves it from being a capital expenditure to an operational one which can make things a bit easier when planning the budget. Also if your business depends on a critical piece of software you need it backed by someone to keep it working.