Because it was veeeeeeeeery slow to me. As someone in East Asia, you are lucky if you can load a hidden service under 10 seconds.
First we should briefly talk about how hidden services work. You have a very long address encoding the portions of a HS public key, which is stored in a special directory (HSDir), and due to the P2P nature of Tor, that basically becomes a DHT/Torrent Tracker
which draws parallel to a DNS service.
Then you initiate a
rendezvous request in HSDir to request a contact with the hidden service.
The hidden service noticed the HSDir updated, then arranges a Tor circuit (of arbitrary length) and then write back to HSDir to tell the requesters to contact via that new circuit which this information will ultimately be signed with the hidden service's private key as a proof of identity so MITM is impossible (like bootleg TLS, or a mock PKI actually)
As you noticed there would be at least three user circuits involved: the hidden service to Tor itself, the Tor end user, and the hidden service relay circuits (I would like to call that a transit tunnel, the middleman).
The more the circuits and relays in between, the more likely your data will fly around the world, and too many circuits is the intrinsic reason why hidden services are very slow.
Recall that each circuit is a linked list and to decrypt the data cells you have to wait for the "pipe" to flow back and forth serially. A to B to C, and C to B to A on back. Due to this recursive relation, no relay preemption is allowed.
Keep in mind the real torspec is very complicated (that took me a few days) and I tried to make a gist for you, and in reality this may not be accurate up to date.
Adding insults to injury, the vast majority of Tor relays are dominantly located in US and EU, and there are barely any Asian Tor operators like me, let alone exit node operators. This caused a serious "geofragmentation"/"geopartition" where one group of people have degraded services over the others.
Fortunately, if your sites are mostly static or deterministic without any serverside dynamic and fancy UI (cough cough PHP and Ruby), given enough patient I would still got what I want. Just that it would have took it for me to be longer than others.
That is why I think SPA and PWA, both client-side oriented application on such a low rate network like Tor hidden service, and abstracting server interaction as low overhead APIs such as gRPC and ttrpc, would be very useful as I was experimenting it before, but most people uses Tor Browser, they would likely be disabling JS with NoScript for...security reasons. They are really afraid there will be 0days in the JS engine that would pop them a dropper. There are couple of heap spraying 0days in V8 but so far Greasemonkey is fine...