I recall we could dial up a super slow connection over telephone lines, get all our mails into such client in less than 4 minutes over said slow line, just to dial off again.¹ Afterwards we would read all our mails offline with all the time in the world, carefully crafting replies and put those into an "Outgoing" folder for the next time we could dial up a connection again (usually the next day). :)

¹) back then you paid Internet by the minute, or in case of the Deutsche Telekom it was a 4 minute tact in the evening, so you had to wait until after 21:00 to get the cheaper prices.

but i'm assuming this is a client for their webmail