I think it heavily depends on the context, but in general it is better to write it normal and not as an abbreviation, if you are not sure, if it will be understood by everybody.
With context I am for example referring to a team working together with a technology, for which we can expect shared understanding, like "CSS" should be known among Web Developers. You do not even need to know, what it would be normally written and can understand the meaning. Of course it is different, if you start to create your own abbrevations. This is similar to not putting some effort into writing chat messages, you know, like not writing properly and everything lower-case or mixed with upper-case.
I think it heavily depends on the context, but in general it is better to write it normal and not as an abbreviation, if you are not sure, if it will be understood by everybody.
With context I am for example referring to a team working together with a technology, for which we can expect shared understanding, like "CSS" should be known among Web Developers. You do not even need to know, what it would be normally written and can understand the meaning. Of course it is different, if you start to create your own abbrevations. This is similar to not putting some effort into writing chat messages, you know, like not writing properly and everything lower-case or mixed with upper-case.
Yep; some acronyms are good. Most (especially the ones someone makes up for themselves, as you said) are not good.