I'm guessing in some way you're looking for confirmation that MA are a worthwhile pursuit in terms of SD because that is something you keep asking about. So to summarise my opinion based on experience:

i) MA training can increase a person's ability to fight. This could be useful in a SD situation.

ii) MA can increase a person's overall spatial awareness, their ability to read body language (to an extent), and focus. All of this can be useful in identifying potentially dangerous situations.

iii) MA should be trained regularly to develop and maintain fighting skills.

iv) Training too intensely is a bad idea as it can fatigue a person or lead to injury (both of which are bad from a SD point of view). It can also be expensive. It can also lead to a person ignoring development of other SD skills (such as flight skills).

v) Many martial arts clubs are ran for profit. As such they can market to people that people "need" MA to stay safe. This is not necessarily true.

vi) If you are going to train MA for SD, train as many ranges as possible (striking, grappling, weapons etc...). It is best to become as proficent as possible in these areas. It may be best to focus at one range at a time. This depends on the person though.

v) Some form of resistance training is essential. Getting too focused on resistance training can be limiting though (e.g. people get use to fighting under certain rules or conditions that may not exist outside of class).

The human being has something called the social gene. Basically, we need each other to survive, so we don't hurt each other. That is hard-wired in to people. This hard-wiring can be short circuited in individuals, but most people are not going to attack you. It's just the way we are.

Training in MA will help you get better at fighting and/or reacting to a violent attack (assuming you are at a competent school).

My advise for you Aplant is to find a reasonably priced school or club and try it for a while. In your area boxing or judo will be cheap and easily available. These are good starting points. You will get more condfident as you train. You may find you are less concerned about being physically attacked as you train because you will feel more comfortable about how you respond to violence as you will be exposed to controlled violence in martial arts classes and you will learn how to react.

The only way to really know if it is good value for money is to go train. That is the bottom line.

Good luck!
"Let your food be your medicine, and your medicine be your food" Hippocrates.