From what I know it's considered "better" because it's one of the first to use things like shadowsocks.
Usually ISP can detect you are using a VPN, some countries/isp actively block it.
With obfuscation it looks like normal trafic thus, harder to block or to detect you are using VPN at all.
"Mullvad's Shadowsocks integration is designed to help users bypass internet censorship and restrictive firewalls by routing traffic through obfuscated bridge servers."
So, it's up to you if it matters or not.
It's tempting to want it by default but it comes at a cost.
I would prefer to have it as an option. Also it's a game of cat and mouse, if shadowsocks becomes popular, they learn to block it better eventually so you need to move to something else. In fact shadowsocks is considered "old", we also have Hysteria, XRay and other...
P.S I don't know why I know these thighs because I don't even have a VPN, i just find it interesting as a technology...