Good for competition?
Tell that to the workers forced to train their visa'd replacements. When you get fired, replaced with a visa scab the company can get away with paying a tenth of your salary, & threatened with the witholding of your severence if you refuse to train the scab, how is that good for the economy? It certainly isn't good for employment, morale, or doing anything besides lining the already fat pockets of the bastards at the top whom reap (rape?) the rewards.
I hate Trump. I won't vote for him. But I agree the visa system needs to be stopped immediately, entirely, permanently.
Want to do business here? Then hire someone whom LIVES here. THAT will help the economy, morale, & convince the public that you're not just a greedy fekhead whom deserves to be strung up by your nipples & used as a pinata.
The same should go for everywhere. Want to do business in Scotland? Hire a Scot. Ireland? Hire an Irishman. England? Hire one FROM there. Don't hire some scab bastard from somewhere else, import them in at the expense of a local, just so you can pay them less, work them longer, & give them the boot (revoke their visa) the moment they realize JUST how shitty you're treating them.
Do business in $Area, hire someone from $Area to do the work, pay them fairly, treat them as if you value them, & don't fall into the fallacy that humans are just replaceable cogs in the grist mill of your profit machine. We have this NASTY habit of throwing a monkey wrench in the gears (striking, unionizing, suing, sabotauge, etc) when you piss us off...
(Edited because I haven't had enough caffeine yet.)