I learned the hard way that spam filters can go off the rails and start discarding much of your legitimate email. I don’t know exactly what happened when my web hosting firm decided to built their own spam filter, but what I suspect may have happened is that the spam filter somehow decided that any mail you discard was spam and began flagging it as such. That may seem a logical assumption, but it is not. What makes that a problem is that much of the legitimate email I read and consider important is nonetheless discarded after I read it, like a print daily newspaper. Likewise, I may not need an invoice after I pay it, but I do need to receive the invoice so I can pay it.
Checking your spam filter can be a nuisance, so most of it don’t do it regularly. But most of us also don’t notice if we stop receiving a monthly newsletter, or invoices that are irregular or infrequent, like a yearly invoice from an you have set on autopay. You might think autopay will avoid that problem, but credit cards expire periodically and you may need to manually change the expiration date and security code. Or the spam filter may helpfully design to bounce rejected non-spam email from a client who wants you to do a project for them with a message saying the address is no longer valid. These things happened to me, and it took to identify the problem, repair the damage, and move my email to another server.
So we really don’t want Google, Apple or anybody else to start identifying some class of email as, say, “solicitation,” which we might reasonably assume applied only ads but also turns out to include invoices for things you purchased.