Even then I will ask to the communities or the polygon investor will think that it will be good idea to hold polygon for long-term or the best will be sell immediately after the recovery?
Matic all-time high is $2.92
The price now after the gain that you posted about is $0.517
Anyone that invested on the coin during its all-time high is losing 5.647 divided of the money the person invested on the coin. Example is someone that invested $1000 on Matic at all-time high. The person's money would be $177.05 by now . That means the person is losing $823 already.
So is it worth investing on the coin in long term when it has no chance to even get to its all-time high?
You are right seriously person is at a high level of lost that is why it's not always advisable to venture the market during bull run, when the market crashes there would be much lost and if time not taken it could be hard for them to bear the lost. This same reason is why people lament investment on cryptocurrency that it's very volatile, and of course it is, why would someone venture into market at the picked without knowing there is every likelihood for a serious dump from the market.