Some people will stop working, and that's perfectly okay, and that's not an argument against UBI - UBI is a solution for an environment with unemployment and unemployable people, so some people stopping working because UBI is sufficient for them is great, it will free up jobs for people who want more than UBI and do want to work.

Some people will spend the money on some way that seems wasteful to you, and that's perfectly okay as well - assuming they're sane adults, it's their business to choose which of their needs matter more and spend the money as they wish; we don't want all the UBI to become a transfer to specific companies running dirt cheap apartments with a food supply program, the recipients having a choice is a good thing that facilitates competition.

Yes, UBI is not a solution to people with major addictions and mental problems; it's not intended to. It does, however, ensure that a person with a mental or drug problem that can't hold a job isn't necessarily required to get their food by begging or crime.

> It doesn't answer all questions. For another example, we won't know how much the results will transfer to other countries.

We won't even be confident the results will transfer to the same country at some later time. Lots of things can change over time alone, let alone across populations.

   people will stop working or spend the money on some wasteful way

That's not really the argument. What does matter is where does the money come from. Cf

  These hand­out incomes are to be given as "an absolute 
  constitutional right," and not to be withheld "under any  
  circumstances." This means that the  
  recipi­ents are to continue to get this in­come not only if  
  they absolutely re­fuse to seek or take a job, but if they 
   throw the handout money away at the races, or spend it on 
   prostitutes, on whiskey, cigarettes, marijuana, heroin, or  
  what not. They are to be given "sufficient to live in  
  dignity," and it is appar­ently to be no business of the 
   tax­payers if a recipient chooses none the less to live  
  without dignity, and to devote his guaranteed leisure to 
   gambling, dissipation, drunken­ness, debauchery, dope 
   addiction, or a life of crime

https://fee.org/articles/income-without-work/

Your claim is contradicted by your quotes which specifically calls out people not working and spending their money wastefully.

Then you did not understand the quote. It's not about an objective morality (what is shameful, wasteful etc. to spend on). Spend the money you successfully exchanged with someone else the way you want it.

The morale case with the argument is that citizen should have their say in how their taxes are spend, and that each of one us have different goals so "living in dignity" cannot be accomplished by UBI.

> Then you did not understand the quote.

Perhaps you picked a bad quote then. That quote pretty explicitly contradicts your claim.

  They are to be given "sufficient to live in  
  dignity," and it is appar­ently to be no business of the 
   tax­payers if a recipient chooses none the less to live  
  without dignity

Dignity is subjective ofc. If you think otherwise I can understand how you can interpret the quote in another way :)

Since dignity is subjective, how can someone (the taxpayer) have any business having an opinion on whether someone else is living with dignity?

I fail to see how the subjectivity of dignity has any relation to your claim that "What does matter is where does the money come from."

They don't have business in it. But they might find how their taxes are spent immoral from their point of view.

UBI will never solve the economic problem of "we all should be living in dignity", ours values are subjective.