Wearing a sequin dress to a wedding can be acceptable, but it largely depends on the wedding's formality, time of day, and the couple's preferences. In general, sequin dresses are more suitable for evening weddings, especially those with a semi-formal or formal dress code. If you're attending a daytime or more casual wedding, it's advisable to opt for a less flashy outfit.
Additionally, consider the colour of the sequin dress. It's courteous to avoid white, cream, or any shade that might resemble the bride's attire, as you wouldn't want to detract attention from her on her special day.
Lastly, always refer to the specific dress code mentioned in the wedding invitation, if any, as it will guide your choice of attire. If you're unsure, it's a good idea to consult with the bride or groom or follow their wedding website for any dress code recommendations. Ultimately, wearing a sequin dress to a wedding can work, but it's essential to do so tastefully and in a way that respects the event's overall ambiance and guidelines.