Playing Card Symbols

[Thomas George]

I am amazed that the playing card symbols spade, heart, diamond and club 
don't appear any of the collections in my Debian Buster programs. I can 
insert them in the text I type by entering CTRL-SHIFT-Uunicode but if 
this text in a Thunderbird email to a friend he receives only the unicode.

I don't understand why these symbols are not as ubiquitous as all the 
smiley faces.