Building a business on blank cheques and accidental spends is shady. It's also a large barrier to adoption. The more times devs see reports like, "I tried [random 20-minute tutorial] and woke up to a bill for my life's savings and luckily support waived the fee this one time but next time they're coming for my house", the less they'll want to explore your offerings.
Even having the option of a hard spend limit would be hazardous, because accounting teams might push the use of such tools, and thereby risk data loss incidents when problems happen.
Hard spend limits might make sense for indie / SME focused cloud vendors though.
Many of these new AWS-provided stacks, however, seem to create stuff all over your account.
The moral of the story? Don't ever use AWS tools like the one the OP describes, ones which create a bunch of different resources for you automatically.
i use them to create a small test stack to look at it for a day or two.
then go through, delete all of the resources, put what i need into terraform etc.
has worked well for me in the past.
but yeah, i would never blindly use aws tools to magically put something into production.