Actually, it is a good reason not to invest in Peru, since the 16% is an average, and thanks to the large informal economy - which generates little or no income tax - the formal companies (the ones who might come here to invest, for example) pay a disproportionately high rate, and you can only tax the formal economy so much before businesses becomes unsustainable. That's not a big selling point!
Check out this graph: https://data.oecd.org/tax/tax-revenue.htm
Peru is not included, but you can see Chile clocking in at 20% (GDP/Tax burden), and the average for OECD countries is closer to 35%.
Higher tax collection would mean better wages for the public sector, helping to attract better workers. It would mean more infrastructure (huge road deficit in Peru), more and better hospitals, schools.... the list goes on.
But it remains super hard to formalize small businesses (even some larger businesses), because business owners are all of a sudden presented with a lot of additional payments (not just income tax) but expenses related to labor (medical, vacations, gratifications.... the expense for an employer is roughly 1.45 x the wage the worker receives.
Lack of formalization and the inability to collect taxes is one of the biggest challenges Peru faces.