Why use TOR instead of Mullvad browser + Mullvad VPN?

Except when there is a necessity or good reason to avoid Tor, I would generally go as far as recommending Tor and Tor Browser for general internet use, and Mullvad Browser + VPN for online services that block or discriminate against Tor users. To answer your question, Tor is designed for anonymity and privacy while AFAIK a VPN (virtual private network) is meant for connecting remote computers together over the internet to form a private network. A VPN may hide your IP address from online services you connect to but AFAIK a VPN session is tied to an account. A VPN is centralized (unless it isn’t) and if an online service or state actor desires to go after someone using a VPN they can apply pressure on the VPN provider.