You can use Excel as a project management tool, and many companies still use it for budgeting, creating timelines, and visualizing data. Part of the reason that project management software is becoming the modus operandi for many sectors and industries is that spreadsheet programs are limiting.
Project management software, to put it simply, just does more and, because there are so many free plans, there's not really a downside. Plus, many even offer a spreadsheet-style view (like Teamwork) or are spreadsheet based (like Smartsheet).