It's real.

Adding a period adds a sense of finality and emphasis, while ending your sentence without one means the tone is lighter. This is inherited from texting habits

https://theconversation.com/why-does-using-a-period-in-a-text-message-make-you-sound-insincere-or-angry-61792

https://www.sciencedirect.com/science/article/pii/S0747563217306192?casa_token=2GuEomfEzyMAAAAA:xnd6UeoYlKC8-DUZBhiC4hh5p3CZefiXL6FX3ku7yTixGEd6pQ_n5BORZ-iFZY_-zz7rP_ArsyY

https://www.sciencedirect.com/science/article/pii/S0747563215302181?casa_token=NC-Hjq5VqI8AAAAA:JKFpxaM-KHvzCSr9Iw0OJVUiMsDh3ecSAQpdnYoFGMfeTm-HakGAVXK3XhYQin6uGrmS-Q2XjX8

https://www.sciencedirect.com/science/article/pii/S089858982030108X?casa_token=L_bofonFo1QAAAAA:yqKmY7po0gXJdUxoBDv4Lw_TGMxb-oeBplHLSKxlZySiBb7Z8nIQmfmMYAB3mfl0SI37fYWY6Ho

https://www.sciencedirect.com/science/article/pii/S0747563215302181?casa_token=FBJrNZQnj-UAAAAA:afZ2QLPX4KeSvY7_LtQ2nfJJCY27fOGrxCpQXP_UegQW1TqSShC0cCVFNVw9ZXyQW51N0Ssoc4Q

Yup, there's a book called "Because Internet" by Gretchen McCulloch that details intergenerational linguistics. Ultimately a lot of the answers boil down to "because internet" thus the name of the book, but it digs into the various causes of linguistic shifts in generations. Interestingly "written" communication has become much more relevant and so people have developed styles, techniques, and quirks to represent themselves. We see trends like young people not ending their sentences with periods, the use of ellipses, capitalization and more

Remember, linguistics is a descriptive science and not prescriptive. You can't control how people communicate but you can observe trends

I can't see why they wouldn't be

See how that sentence got that soft landing as opposed to this one that informs you of the nature of the statement it's at the end of? The first one doesn't direct you to get excited or to take the statement as a question, but it also doesn't give the hard ending of a period. It lets the sentence "breathe"

I'm not a professional linguist, but I can confirm. It's about trying to set a tone for your written sentences. We don't use periods when we talk in real life, you know? Adding them to a text makes it read too serious