omexlu All messages are on the xmpp server, so it does not matter what client you use - messages are available everywhere (similar to imap in the email world)
regarding the 2,50 - a couple of years ago it was in my opinion the best client all others where rubbish at that time- it’s worth the money.
Anyway feel free to try other clients, you can use as many as you like - it does not hurt - as you can use them at the same time - just enter your credentials and you have your message history on hand (in case the client supports it - conversations does it ^^)