Is a second shower bath sensible?

cool, we are finally people with more money

We have counted the bathroom in from the start. We're just unsure if it’s really worth it for us.

Let’s go partying, Sebastian – first time I’m hearing about it
I immediately told my wife and asked where she’s stashing the money

Hello,

for a while now, we have been dealing with the question of whether a second shower bathroom makes sense or not?
We are currently two adults and an almost 6-year-old child.

On the ground floor, we have a small guest toilet without a shower.
On the upper floor, there is the main bathroom with shower and tub. The bedroom as well as a children's room will be there for now.
In the attic, we could install an additional shower bathroom.
There is the office / guest room (14 sqm) as well as another children's room (17 sqm), for possibly more children.

We are building a semi-detached house with a developer and cannot decide.

Our current pro / con list:

Pro:
- a separate shower for guests on the same floor
- if the child grows older and possibly moves upstairs or has visitors, there would be a separate area
- if we are ever four people (one adult + two school children who would have to leave the house at the same time), there is another bathroom and no one has to wait in line. Although there is still the guest toilet

Contra:
- the additional costs which could certainly be planned better elsewhere
- in my "youth" there was only one bathroom with a tub for all residents and it worked fine
- when we visited somewhere, we also rarely had our own shower bathroom, and it was completely fine for us
- currently we have a mini bathroom with only a shower and there have been no problems so far, even when we had guests.

Another factor, should we decide on another shower bathroom, besides the price is the service. There are 3 options.
1. Pipe installation for warm and cold water including fan preparation
2. Shower bathroom preparation (requires point 1) would be building a wall, sockets, lighting, etc.
3. Final construction (requires points 1 & 2) would be with shower tray (I think also shower wall), sink, and toilet

Tiles would be extra on top of that.

We have thought about selecting only the pipe installation for this case and then building the walls sometime later.
Then the further question would be how lighting and electricity would work?
However, the whole attic would have to be changed and renewed then as well.

Or choose point 1 and 2 and complete the finishing work later.

Maybe one or two others here have further pro / con thoughts on this.

Thank you