Multiple Email Addresses To Address A Need

So first you may ask why have more than one e-mail address.  After all, doesn't this make life more complicated?  Yes and no.  For about 15 years now (maybe 20),

PROs

Forwarding:
I have a forwarding e-mail address that allows me to give out one email address and have it forwarded to the address that I think is most appropriate.  This has helped significantly when I have had to switch between emails for work, redirect e-mails for job seeking, sign up for various services that require e-mail verification, etc.  I can forward e-mails based on different rules I have defined (so that an email containing something to the effect of "welcome to ..." goes to an e-mail address that doesn't need to reply while a password reset email goes to a different address).

Professional:
I use a professional e-mail for all correspondence that needs such an address.  For instance, my technical certifications are always sent to the same address.  I use a different e-mail alias for legal matters than I do for everyday ones.

Special:
I have one email that sends and receives e-mail as encrypted, by default (you can get this to work with any e-mail address, but not by default).  This is extremely important when it comes to sensitive documents that need to be signed or are signed and I need to send them out.

Hidden forward auto-forwarder:
Many places now provide this as an option.  Firefox has something called Relay that makes up an e-mail alias for you that will forward to an address of your choosing.  This can come in extremely handy if you do not want to get tons of e-mails sent to you by telemarketers.  One of the e-mail programs I use, proton, provides this as a service after a certain level.

CONs:

E-Mail readers:
By far the biggest CON is that you may need to use more than one email reader in order to check your e-mail every day.  This can be a major drawback.  After all, I got into this hoping to make my life easier not harder.

The easiest answer to this con is to use one e-mail reader to read them all (yes I meant that one).  This is entirely possible to do, although it might defeat the purpose of having at least one of the alternate e-mails.  Proton is best left on the web.  If you really want to maintain the confidentiality and encryption that Proton offers, it is a mistake to try to combine it with other email addresses.

NOTES:
I should mention the following:

I have been told by a good lawyer that mail by Google (GMail) is one of the least secure e-mails.  
Checking multiple e-mails can get tiresome.  I read all my e-mail accounts, except my proton account, from MS Outlook.  Outlook may not be the best program out there, but it does make it easy to read your email (on my phone I use Nine).  

Although you can make many email addresses for free on a service like google (mail.google.com), like I said previously, it is not very secure (there is n encryption plugin though).  I have one e-mail hosted through one of my websites, one e-mail through google, one e-mail through proton (which has 3 aliases right there), and one e-mail through a paid mail service, which I use for forwarding.  So that comes to 3 basic e-mail addresses, not counting aliases. If I add aliases, browser plugin maskers like Firefox Relay, and other free e-mail addresses, it comes to over 10 e-mail addresses.  

I have mostly kept all these addresses in one place so that I can easily read incoming mail, but once in a while, like with my proton email(s), I need to use an alternate e-mail reader.

All-in-all I find that having multiple e-mail addresses is easier than not having them (I tried using rules in Outlook and ended up with over 400).