Ready-made tools usually charge per user per month, so the bill goes up every time somebody joins the team. At rates of the order of PLN 100–PLN 200 per person per month, a company of 50 pays as much for the right of access alone as a full-time salary costs.
A bespoke system on your own server has no per-user fee. Maintaining a solution like that for a team of around 50 is in the region of PLN 300 a month, the equivalent of a handful of licences, whether 10 people use it or 50. Development work comes on top, but you order that when you need it, not every month.
That does not mean a bespoke system always wins. With a small team and a standard process a ready-made tool is often cheaper and quicker, and in that case that is what we say. The balance only tips once the team grows, or the process stops fitting into what the ready-made tool can do.