What would be the advantage of enhance on ARM ?
In production as a shared server, lets get real, limited. Anyone serious is still going to be buying an AMD or Intel rig.
But for roles like DNS, it opens up VPS options such as from Hetzner and Oracle which are very affordable despite offering excellent performance.
It also allows more hobby users to host sites or roles on equipment like Raspberry PI's etc which are now at a performance (not reliability) that could be very interesting.
Would it be suitable for bigger webshops, like 10.000 products and 200 big orders a day?
No. Frequency and IPC are king for PHP and MYSQL due to each connection being single threaded for the most part.
For your WordPress sites and webshops you want the fastest highest clocked CPU's you can find. ARM has come a very long way in recent generations but it's not comparable in raw single threaded speed.
Saying this I do rent a dedicated Hetzner ARM64 RX server as a dumping ground to host mostly static files, landing pages and basic PHP pages for large events and the thing absolutely fly's.
Maybe if Enhance supported ARM64 I would consider adding it into the cluster.