there isn't a massive difference in performance.
i've not done a lot of comparison, but in using a different web management panel with AWS EC2 instances,
both x64 and arm (aws own graviton cpu's) i found identically sized instances to be very similar in performance,
arm possibly just edging it slightly, but that was on perception rather than any scientific, measurable testing metrics.
the studies i have seen comparing them show them to be generally equal in terms of performance
the big advantage is arm based servers / vps's are significantly cheaper to purchase, and also more power efficient.
so the potential cost savings in switching to arm are very compelling, especially as margins are getting squeezed tighter all the time.