If you choose to host your website with a web host that uses only one bandwidth provider to connect to the Internet than you are at risk of not being reachable. There is no real issue with having a web host that has only 1 or 2 links to the Internet. The issue is when your web host has only 1 or 2 links to the Internet and they become not usable.
Single bandwidth provider
If your web host has only a single bandwidth provider and that connection is saturated than do not expect to be able to access your websites. If any accidents like a fiber cut or the web host experiences a DDoS attack. Your websites won’t be reachable. Having a single connection to the Internet is like having one road leading to and away from your home. If anything were to happen to that road than there will be difficulties to get to and from your home.
2 bandwidth providers
When your web host has 2 bandwidth providers instead of 1 it is better but not really. If one bandwidth provider were to experience any issues than the remaining traffic will get transferred to the other bandwidth provider. If that other bandwidth providers connection to your web host isn’t designed (capacity) to handle all your web host’s traffic than you may have issues accessing your sites.
Affordable if not really cheap
If your web host has only 1 or 2 bandwidth providers than there is a high chance that their pricing is a lot lower than other web hosts. If your web host has only 1 or 2 bandwidth providers than they may decide to pass the savings onto their customers. This results in a lower monthly fee.