Edit: If so, why?
The big downside in my eyes is that it's TCP-based, so your latency properties with non-TCP connections aren't what you want (e.g., you can't meaningfully use Mosh) and if the connection drops / your IP changes, your single connection goes down and you have to restart it manually. Wireguard is UDP-based and handles roaming, so even if you switch networks, your tunneled TCP connections are fine.
Also, it's a real network connection, so non-TCP/UDP things like ping work, you get an actual failed connection when the remote server doesn't respond instead of a successful one that drops immediately, etc. If you have root on both sides of the connection, ssh -w will also get you a real network device. (But also if you have root on both sides, you might as well set up an actual VPN.)
The most compelling aspect of sshuttle, in my opinion, is that any host running sshd can be an endpoint - no software is required. As long as the sshd in question has python available, you can use it as an endpoint.
my point is: on all setups you have traffic that might go around the vpn tunnel, that is an application defect not that ssh tunels are worse.