Can someone please explain to me why they can't create the account even if it is used as disposable? Storing one text file with the login on their side does not cost much storage at all.

This happens to me occasionally already as a paid Fastmail user. I switched from Gmail about a year ago and I can’t change my existing Yahoo account to use Fastmail.

I get it, we deal with fraud and abuse from throwaway emails all day at work, but it is frustrating for sure.

Every ~3 to ~5 years I change my free email addresses (gmail, hotmail/outlook, yahoo, etc.). Although, I don't use yahoo anymore.

I have turned a few of my old gmail accounts into spam mail trawlers as I “Gotta catch ’em all! ” and every time I have to make a temporary or single use account for a service I want to check out/try or I just foresee making only a single purchase I always use a gmail account+alias if they don't have a guest checkout option. The old gmail accounts are checked quarterly on a if-I-remember basis but at least once a year.

On first contact with any business, services or people I have never met in person I usually give a newer gmail address I check biweekly in case my forwarding filter missed something important.

Moreover, I use gmail incoming mail rules to forward copies of important keywords and specific email address to my 2 professional (redundant) emails for which I enabled notification on my phone, main desktop and workplace.

Gmail is so ubiquitous and well trusted that I can pretty much use it in any input forms for registration or verification. Their spam filter is also pretty good (not always) to skip/pre-filter obvious phishing and scam emails.

Even though I have already moved away or avoided Google, Microsoft, Meta/Facebook, LinkedIn, Apple, TikTok, Wechat, Temu, PayPal, Sony, etc. I occasionally still have to indirectly deals with them on a limited case-by-case but specific situations.

By excluding so many excellent email services they are inadvertently making sure that Gmail, Outlook and other allegedly "reputable" free emails services slowly become a junk/spam/marketing email dump that few would want to enable constant notification for and fewer would want to delve into and sift through daily.

Sorry, this became a long rambling rant about all the layer of protections I have to use nowadays to just avoid wasting energy and attention on the profusion of spam/useless emails.