It is impossible to have a perfectly seamless gutters!
Why?
Because there are corners and end caps. Guess what? These areas can leak if not properly sealed or if time does its thing and erodes or cracks the seal.
It is very common and can be fixed without replacing the entire gutter system.
Water can do some pretty amazing damage over time just one drip after another. When a seam drips the water runs down to the fascia and soffit. When this happens the wood will eventually rot. When it rots it can get really expensive to replace it because the gutter has to be removed and then the wood removed and replaced and then the gutter put back up.
Or...you can have us come out and seal the seam to prevent all that damage and expensive repair service.