Advantages of WKO+ are that you buy it once and use it forever, rather than get milked out of more money every single month. Another upside is that there's no internet connection required. Sometimes I might do a big ride out in some remote place I'm vacationing in, and it's nice to be able to look at the data before I get home a week later. Not a huge deal, but it's something.

I've not really spent much time in TP online because I didn't like it, so I can't really give counter arguments as to why it may be better.

Now that strava premium does power curves and TSS accumulation I use WKO+ much less.