‘valuable’ is a relative term, and it ultimately depends of what you do with the knowledge obtained during your certification course that counts.
Having said that, if you are looking for employment with a certain facility, you may want to check their requirements.
ACSM which you mention is a highly respected certification and was long held as the ‘standard’ even though (personal opinion) there are other certification of equal standing.
After looking over W.I.T.S.’s website and reading into them some, they seem reputable to me. They’re also a National Board of Fitness Examiners Accredited Certification according to IDEA (https://www.ideafit.com/certifications/personal-trainer?pid=25) which is good news.
Regardless, I agree with Karin’s statement that “‘valuable’ is a relative term.”
Upon gaining the certification through W.I.T.S. do you feel prepared to help clients achieve their goals? Also, if you don’t plan to go into business for yourself, does the company you hope to train for accept the certification as a prerequisite to train there?
If you answered “yes” to both of those questions you’re probably good to go. Would you disagree for some other reason?
They are a good certification to have as a baseline as are many others. I think the more important thing is to keep up with continuing education that will satisy the needs or wants of your clients. Even if you are not getting certified in an area of interest of your clients, at least educate yourself with material that pertain to your population. Clients do want to know that your certified but want results on what they are there for or learn something from you. I feel that it is our job to do research on areas of interest for our clients. They have their own jobs to worry about and research.