There are a lot of things being conflated on this thread.
Firstly the terms therapist and counsellor are not protected titles and could mean anything - from someone who has done a short course to someone with multiple relevant degrees at doctorate level.
There are also multiple approaches and they should be used at the right time for the right person based on a decent shared understanding of the problem. This should be drawing on as much evidence as possible (and yes our evidence base about anything to do with mental health isn't perfect because our brains are a lot more complicated than other parts of our bodies). So someone might come for trauma therapy and the best approach might be trauma focused CBT (tf-CBT) or EMDR. Or other approaches such as NET, which don't have sufficient evidence to make it into NICE guidelines yet. But a good therapist will assess this and if they can't offer what they think is best, they would refer on. This should always be within a supportive and collaborative relationship (these factors are very significant). But 'Having a chat' is 100% not an evidence based approach to processing trauma (or most things that therapists might help with). Often when things don't shift it is precisely because the therapy focus has shifted more into a chat like territory rather than focusing on strategies and theory driven practice.
CBT is often used as a catch all term but if you analysed it, you would undoubtedly find a whole host of stuff going on that wasn't really CBT, or was a diluted version. And even if it is CBT in principle, it doesn't mean it is necessarily 'good' CBT. If you gave me some nails and wood I could probably knock up a rudimentary bench. Give a carpenter the same tools and I'm sure the results would be very different, even if on the surface we were both building something with wood and nails.
There's no reason why someone in an abusive relationship shouldn't access therapy. But if they are still at risk, then the type of therapy would be adapted. So you wouldn't do work around processing traumatic things that have happened, but you might help them to see that they are entitled not to be treated this way (and leave if they choose to) by helping to build up their self-esteem that has been chipped away by their partner.
Therapists would never do therapy for their friends - it's against various codes of conduct to have personal relationships with clients- for a host of different reasons. It's completely not the same as having a chat with your mate.
Also i'd just like to point out that I don't work privately so have no vested interest in pointing out any of the above. I do agree that there is poor access to government funded psychological therapies in many areas, to the detriment of everyone, including the many who cannot afford to pay. But for those that can, why should they not also be able to choose to access a paid service, like any other service we might pay for?