The place is owned by limehome - a Germany-based company that runs reception desk-free hotels. What it means is that they put the burden of going through the registration process - complete with taking selfies and scanning one's passport - squarely on you. Their system is somewhat confusing and requires significantly more than the "5 minutes" their emails advertise. Perhaps this is how they keep the rates on the cheaper side, sort of like how some grocery stores turn you into an employee at the self-service checkout.
The hotel itself is in a great location. The room was very bare-bones - three single beds, two end tables, a TV, and not even a desk. It is ok for a one-night stay, but for long-term stay, there are basically no amenities in the room (no fridge, no desk, only one chair for a room where presumably three people are staying).
If it is the cheapest available accommodations in Porto, and your stay is short, and if you are ok with the "fill out a bunch of web forms, scan your passports and take selfies, then wait to receive an access code" setup - go for it.
One last note: the code you get to enter the room and the building are the same and they are only four-digit codes. I feel like longer codes would be safer.
