Sealing wax has been used from the past until today. In terms of authenticity, both sealing wax and common seal stickers work. However, if one were to count it based on how long it’s been a practice, sealing wax takes the lead. Sealing wax is more difficult to replicate since you are required to physically melt and drip the wax down and you cannot predict it’s flow.
When it comes to convenience, common seal stickers are a lot more convenient and easier to use since you just need them and the common seal. Sealing wax requires more time since you need a lighter to melt the wax and allow it to drip enough onto the document to be sealed. You also need to carry around your common seal so it can be rather inconvenient if you have to travel.
If you are someone who values the overall aesthetics of things, using sealing wax might be right up your alley since it closely resembles the old time practices of the past. It also casts a dramatic yet strong effect so it looks a lot more personal. Common seal stickers however, come in standard shapes and look mass produced.
The safety of your documents are important too. Sealing wax is a lot easier to open if you scrape the wax off. Alternatively, sealing wax is hard to cover up if the legal document has been opened so you can easily tell if it has. Common seal stickers however are difficult to peel off but they are also easier to replicate as long as you stick another above the broken one.