Joseph, There may be holiness – Kedusha in every Minhag (community custom). But they become like “vows” Nedarim, except on a community instead of on an individual level. Chazal (Torah leadership 1500 to 2000 years ago) warned making vows except in the most extraordinary circumstances. Minhagim can create divisions between communities, just as vows create divisions between individuals.
Finding out that your spouse has wrapped himself or herself in vows of prohibition can be grounds for divorce if the spouse is unwilling to go to a Jewish court to get the vows released (“permitted”).
The husband has the power to nullify vows of the wife on the day hears about them if they involve personal suffering or affect their relationship. If he fails to do so, and the vow affects their relationship or cause suffering he will be held at fault for failing to nullify.