Split tunnel means we only want certain networks to use the VPN when traffic originates from the client. That way they do not have to send all of their Internet and other traffic across the VPN when they are connected.
Some people argue that split tunnel is less secure as it potentially exposes the endpoint to a greater number of threats and risks them not being compliant with the organization's acceptable use policy while connected to the VPN.
Others argue that the risk is acceptable when balanced against the need to otherwise backhaul all of the remote users' Internet traffic.
Not allowing split tunnel can also be problematic if the remote user is not at home but at another organization's network where they need to access non-local resources while being on the VPN. For instance, a network shared drive for a vendor VPNing into your network for legitimate purporse may be unavailable unless split tunnel is allowed.
What's best for you is a local decision.
