It would not make any sense to publish a site on autoeroticity without holding that masturbation is something good or desirable (except if one was in the porn business, which I am not). I suppose it goes without saying that every kind of (consensual) sexual activity feels good, including touching oneself, but some people feel that it is not good because it is immoral or because it could have detrimental effects on your health. Here's what I think about it:

1. Almost all claims of masturbation having bad effects have proven wrong

In the early history of mankind, masturbation has mostly been seen as normal and acceptable, until most religions declared it sinful during the past millennium, with the exception of Daoism which holds that, regarding men, masturbation is ok and healty as long as you do not spill your semen which contains a lot of "Chi", so I assume it is ok for women anyway.

Religious zealots have added to the religious ban on masturbation by claiming that it is detrimental to health in many ways. But none of the claims of direct negative health effects could withstand scientific scrutiny. No, you won't get hairy palms, your bone marrow will be fine, and if masturbation was really inducing acne, most men would walk around with a face full of pimples all their life.

Regarding negative side-effects, there are two points worth considering:

1. Everything that feels good and thus activates the brain's pleasure center can get addictive. So masturbation can be detrimental when it gets compulsive in a way that the need to masturbate is interfering with your everyday life in a negative way, in the same way as there are sex addicts.

2. It seems that some men (and also women, I suppose) do get so hooked on a certain way and amount of stimulation during masturbation, or get dependent on visual stimulation by watching porn, that they cannot have satisfying sex with a partner any more.

To counteract this, it helps to make masturbation more than just a three minute event of franticly rubbing your genitals while watching porn in front of your screen or with your smartphone (the autoerotic counterpart of a 'quickie'). As sex with a partner, autoerotic pleasure should be celebrated, should be something creative.
Masturbation profits a lot of change, as sex does. It can have the same phases as mutual sex: The 'foreplay' which is worthwile in its own right, the phase of stimulation that leads to climax, and the relaxation phase. On this site, you will find many tips, ideas, and exercises on how to enrich your solo sex habits.

2. Masturbation is beneficial in many ways

A brief search results in many possible benefits. Here's an incomplete list:

In general, i.e. for both sexes:

• Needless to say, but I still say it: It just feels absolutely wonderful. We all got the present of a body with endless possibilities of giving us pleasurable sensations. So why not cherish it?
• It creates a sense of well-being and makes you feel good about your body.
• It is free!
• There's are no risks like acquiring a sexually transmitted disease (or cathing other 'germs' like Covid-19) or unwanted pregnancy.
• It helps to get to know your body better,  which can also improve your sex life with your partner. When you know what stimulation is good for you, your satisfaction in sex will profit.
• During masturbation, you have more control over the stimulatione than during sex with a partner. Thus, many people experience more fulfilling orgasms during masturbation.
• It provides sexual pleasure for people without partners, including the elderly, or those who choose to abstain from sexual activities with another person.
• It reduces stress and sexual tension.
• Sexual pleasure is a great way to clear your mind of ruminating and excessive anxiety. It brings you to the present moment, kind of like meditating.
• You'll get a surge of the hormone prolactin, which will help you fall asleep afterwards.
• It can be an excellent cardiovascular workout (depending on the way you do it).

Specifically for men:

• A high ejaculation frequency has been found to correlate with a decreased risk of prostate cancer.
• It probably helps to increase your testosterone level.
• It improves the fitness of the sperm by expelling the older ones more regularly.
• Masturbation can improve your ability to maintain your erection, and delay your orgasm. Your partner will love that.

Specifically for women:

• It releases dopamine which actively decreases your perception of pain, e.g. it can reduce the pain of menstrual cramping.
• It strengthens muscle tone in the pelvic and anal areas, reducing chances of involuntary urine leakage and uterine prolapse.