I do, I use stuff like WhatsApp and Discord too mainly of course, but an SMS is fast and reliable, as opposed to the others that require a decent data signal on both the sender and receiver (which is often lacking on my network unfortunately).
Plus, I can schedule SMS messages for a particular time so as to not wake the recipient up if I want to send them a message in the middle of the night, very handy!
Plus, I can theme my SMS app however I want, changing colours, fonts, etc, to be exactly what I like, as well as picking out an SMS app that has the features I’m looking for in the first place (I recommend Chomp). I find applications like WhatsApp to be extremely limited in this regard. Not a deal breaker, but I do love customisability and choice.
I certainly don’t use SMS anywhere near as much as Discord, but it’s wonderful to have it, and I use it regularly :-D
P.S I’ve wanted to use Signal for years but nobody I meet uses it :-( Such a shame, it seems neat!
P.P.S Telegram looks neat too, unfortunately again the adoption with people I know is strangely just 100% furries and nobody else, so I stick to the client that everybody uses rather than having a bunch of them installed (Discord & occasionally WhatsApp).