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.
Excuse me for a minute, I have to go reset my password that expires every 10 days and can not match any previous password and enter my enterprise mandated sms 2fa because authenticator scary -- woops my SharePoint session expired after 120 seconds of inactivity let me just redo that -- oh what's that my corporate vpn disconnected because I don't have the mandatory patches applied, let me just restart -- Woah would you look at that my network interface doesn't work anymore after that update -- yes yes I'm sorry I know my activity light on MS Teams turned yellow for 5 minutes I'm working on it, just gotta do these other 12 steps so I can reset my password to -- oh look it's time to fill out the monthly company values survey, what's that, it's due by end of day?