Agreed. Paying your TR is something that gives you a chance with a few airlines, but ultimately might bite you in the arse further down the line when it comes to an interview with a reputable carrier. Financially, it suits the lo-co's to get SSTR's online. Equally there is no substitute for progressive experience through the likes of TP operations etc.
A long time back, I made the grave mistake of naively fronting up some cash for (what I believe is termed in the UK) an LPC and some line time. I then worked for that operator for a while (and a crap, cowboy operator they were indeed!) Upon subsequent application to other operators in that area, it became quite apparent the disdain and disapproval that was cast upon me for having gone that route and it took great efforts on my part to convince certain CP's that I was worth hiring.